Answer:
93.15 %
Explanation:
We have to start with the chemical reaction:
[tex]CaCl_2~+~Na_2CO_3~->~CaCO_3~+~NaCl[/tex]
Now, we can balance the reaction:
[tex]CaCl_2~+~Na_2CO_3~->~CaCO_3~+~2NaCl[/tex]
Our initial data are the 15.71 g of [tex]CaCl_2[/tex], so we have to do the following steps:
1) Convert from grams to moles of [tex]CaCl_2[/tex] using the molar mass (110.98 g/mol).
2) Convert from moles of [tex]CaCl_2[/tex] to moles of [tex]CaCO_3[/tex] using the molar ratio. ( 1 mol [tex]CaCl_2[/tex]= 1 mol of [tex]CaCO_3[/tex]).
3) Convert from moles of [tex]CaCO_3[/tex] to grams of [tex]CaCO_3[/tex] using the molar mass. (100 g/mol).
[tex]15.71~g~CaCl_2\frac{1~mol~CaCl_2}{110.98~g~CaCl_2}\frac{1~mol~CaCO_3}{1~mol~CaCl_2}\frac{100~g~CaCO_3}{1~mol~CaCO_3}=14.16~g~CaCO_3[/tex]
Finally, we can calculate the yield percent:
[tex]%~=~\frac{13.19~g~CaCO_3}{14.16~g~CaCO_3}*100=93.15~%[/tex]
I hope it helps!
The percentage yield obtained when excess sodium carbonate, Na₂CO₃, is added to a solution containing 15.71 g CaCl₂ is 93.2%
We'll begin by writing the balanced equation for the reaction. This is given below: [tex]Na_{2}CO_{3} + CaCl_{2} - > CaCO_{3} + 2NaCl[/tex]Molar mass of CaCl₂ = 40 + (35.5×2) = 111 g/mol
Mass of CaCl₂ from the balanced equation = 1 × 111 = 111 g
Molar mass of CaCO₃ = 40 + 12 + (16×3) = 100 g/mol
Mass of CaCO₃ from the balanced equation = 1 × 100 = 100 g
SUMMARY
From the balanced equation above,
111 g of CaCl₂ reacted to produce 100 g of CaCO₃
Next, we shall determine the theoretical yield of of CaCO₃. This can be obtained as follow:From the balanced equation above,
111 g of CaCl₂ reacted to produce 100 g of CaCO₃.
Therefore,
15.71 g of CaCl₂ will react to produce = [tex]\frac{15.71 * 100}{111} \\\\[/tex] = 14.15 g of CaCO₃.
Thus, the theoretical yield of of CaCO₃ is 14.15 g
Finally, we shall determine the percentage yield. This can be obtained as follow:Actual yield of CaCO₃ = 13.19 g
Theoretical yield of CaCO₃ = 14.15 g
Percentage yield =?[tex]Percentage yield = \frac{Actual}{Theoretical} * 100\\\\= \frac{13.19}{14.15} * 100\\\\[/tex]
= 93.2%Therefore, the percentage yield of the reaction is 93.2%
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Which of the following is a conjugate acid-base pair in the reaction represented by the
equation below?
H2PO4 + H20 H3PO, + OH
H2PO, and H2O
b) H,PO, and OH
c) H2PO, and H3PO,
None of the above
Answer: [tex]H_2PO_4[/tex] and [tex]H_3PO_4[/tex]
Explanation:
According to the Bronsted-Lowry conjugate acid-base theory, an acid is defined as a substance which looses donates protons and thus forming conjugate base and a base is defined as a substance which accepts protons and thus forming conjugate acid.
For the given reaction:
[tex]H_2PO_4^-+H_2O\rightleftharpoons H_3PO_4+OH^-[/tex]
Here, [tex]H_2O[/tex] is loosing a proton, thus it is considered as an acid and after losing a proton, it forms [tex]OH^-[/tex] which is a conjugate base.
Similarly , [tex]H_2PO_4^-[/tex] is gaining a proton, thus it is considered as an base and after gaining a proton, it forms [tex]H_3PO_4[/tex] which is a conjugate acid.
Thus [tex]H_2PO_4[/tex] and [tex]H_3PO_4[/tex] is a conjugate acid-base pair in the reaction represented by the equation below
The Bronsted-Lowry conjugate acid-base hypothesis defines an acid as a substance that loses protons and donates them to another chemical to produce conjugate base, and a base as a substance that takes protons to generate conjugate acid.
Thus, a proton is being lost, making it an acid, and once a proton is lost, a conjugate base is formed. Similar to that, is gaining a proton, making it a base, and then it produces a conjugate acid after gaining a proton.
The Brnsted-Lowry hypothesis, often known as the proton theory of acids and bases, is an independent theory of acid-base reactions that was put forth in 1923 by Johannes Nicolaus Brnsted and Thomas Martin Lowry.
This theory's central idea is that when an acid and a base interact, the acid creates its conjugate base and the base creates its conjugate acid by exchanging a proton (the hydrogen cation, or H+).
Thus, The Bronsted-Lowry conjugate acid-base hypothesis defines an acid as a substance that loses protons and donates them to another chemical to produce conjugate base, and a base as a substance that takes protons to generate conjugate acid.
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Hcl and 1-isopropylcyclohexane formation
Answer:
Spahgetti
Explanation:
What is it called when a gas changes into a liquid?
Answer:
Explanation:
Condensation is the word you seek.
Answer:
Condensation
Explanation:
When a gas is subjected to decrease in temperature it is condensed
Barium is a very reactive metal in the presence of oxygen and water, thus its density cannot be measured by water displacement. Instead, mesitylene (C9H12, density = 0.86370 g/mL (at 20 o C)) is used. 77.240 g of Ba is placed into a flask, and mesitylene is added so that together the total volume is 100.00 mL. The mass of the mesitylene and Ba together is 148.792 g. What is the density (in g/mL) of the Ba at 20 o C?
Answer:
The correct answer is 4.502 g per ml.
Explanation:
Based on the given question, the sum of the mass of mesitylene and barium together is 148.792 grams. The mass of barium given is 77.240 grams. Therefore, the mass of mesitylene will be,
Mass of mesitylene = Total mass - Mass of barium
= 148.792 - 77.240
= 71.552 grams
The density of mesitylene is 0.86370 g per ml. To calculate the volume of mesitylene, the formula to be used is,
Volume = mass / density. Now, putting the values we get,
Volume = 71.552 / 0.86370 = 82.8436 ml.
As the total volume is 100 ml, therefore, the volume of Ba will be,
Volume of Ba = 100-82.8436 = 17.1564 ml
The density of Ba at 20 degree C can be calculated by using the formula,
Density = mass / volume. Now putting the values we get,
Density = 77.240 g / 17.1564 ml
= 4.502 g per ml
a gas obeys the equation of state p(v-b)=RT.for the gas b=0.0391L/mol.calculate the fugacity coefficient for the gas at 1000°c and 1000atm
Answer:
The fugacity coefficient is [tex][\frac{f}{p} ] = 1.45[/tex]
Explanation:
From the question we are told that
The gas obeys the equation [tex]p(v-b) = RT[/tex]
The value of b is [tex]b = b = 0.0391 \ L /mol[/tex]
The pressure is [tex]p = 1000 \ atm[/tex]
The temperature is [tex]T= 1000^oC = 1273 K[/tex]
generally
[tex]RT ln[\frac{f}{p} ] = \int\limits^{p}_{o} [ {v_{r} -v_{i}} ]\, dp[/tex]
Where [tex]\frac{f}{p}[/tex] is the fugacity coefficient
[tex]v_r[/tex] is the real volume which is mathematically evaluated from above equation as
[tex]v_r = \frac{RT}{p} + b[/tex]
[tex]v_r = \frac{RT}{p} + 0.0391[/tex]
and [tex]v_{i}[/tex] is the ideal volume which is evaluated from the ideal gas equation (pv = nRT , at n= 1) as
[tex]v_{i} = \frac{RT}{p}[/tex]
So
[tex]RT ln[\frac{f}{p} ] = \int\limits^{1000}_{o} [[ \frac{RT}{p} + 0.0391] - [\frac{RT}{p} ]} ]\, dp[/tex]
=> [tex]RT ln[\frac{f}{p} ] = \int\limits^{1000}_{o} [0.391 ]\, dp[/tex]
=> [tex]RT ln[\frac{f}{p} ] = [0.391p]\left | 1000} \atop {0}} \right.[/tex]
=> [tex]RT ln[\frac{f}{p} ] = 38.1[/tex]
So
[tex]ln[\frac{f}{p} ] = \frac{39.1}{RT}[/tex]
Where R is the gas constant with value [tex]R = 0.082057\ L \cdot atm \cdot mol^{-1}\cdot K^{-1}[/tex]
[tex][\frac{f}{p} ] = \frac{39.1}{ 2.303 *0.082057 * 1273}[/tex]
[tex][\frac{f}{p} ] = 1.45[/tex]
What happens at this point
Answer:
What are you referring to exactly
Explanation:
Answer: C
Explanation:
There is a difference in air pressure. That's what I put and I got a 92.
The pyruvate dehydrogenase complex is subject to allosteric control, especially inhibition by reaction products. The main regulatory process controlling pyruvate dehydrogenase's activity in eukaryotes is
a. exchange of ADP and ATP on the pyruvate dehydrogenase complex.
b. phosphorylation by ATP, which turns the complex on, and dephosphorylation, which turns the complex off.
c. AMP binding to and activating the enzyme.
d. phosphorylation by ATP, which turns the complex off, and dephosphorylation, which turns the
Answer:
D. Phosphorylation by ATP, which turns the complex off, and dephosphorylation, which turns the complex on.
Explanation:
The pyruvate dehydrogenase complex (PDH) is responsible for the conversion of pyruvate to acetylCoA, the fuel for the citric acid cycle.
The regulation of the activity of PDH is allosterically by the products of the reaction which it catalyses. These products are ATP, acetylCoA and NADH. When their is sufficient fuel available for the needs of the cells in the form of ATP, the complex is turned off by phosphorylation of one of the two subunits of E1 (pyruvate dehydrogenase). This phosphorylation inactivates E1. When the concentration of ATP declines, a specific phosphatase removes the phosphoryl group from E1, thereby activating the complex again.
An ideal gaseous reaction occurs at a constant pressure of 35.0 atm and releases 66.8 kJ of heat. Before the reaction, the volume of the system was 8.20 L. After the reaction, the volume of the system was 2.21 L. Calculate the total change in internal energy for the system. Enter your answer numerically in units of kJ.
Answer:
U = -45.557kj
Explanation:
Before we can calculate the totally internal energy change in kilojoules firstly we need to calculate W
U=q + w .
We know that
w = PΔ V
where P is the pressure of
and V is the volume
then we can calculate the work
w = 35 atm * ( 8.20L - 2.21L)
W=35atm* 5.99L
W=209.65atmJ
But 1 atm = 101.325J
then ,
w = 209.65* 101.325 J = 21242.79 J
let us convert it to Kj
But we know that 1kJ = 10^3 J .
Then w = 21.243 kJ .
Then we can now calculate the internal energy as
U = 21.243- 66.8 kJ = -45.557kj
But we know that heat was released. Theeefore, the total internal energy change was -45.557kj
How do the particles in plasmas compare with the particles in solids?
Answer:
Plasmas and solids are both made up of cation-anion pairs. Solids and plasmas are both made up of electrons and cations. Solids are made up of cation-anion pairs, but plasmas are not.
Answer:
Solids are made up of cation-anion pairs, but plasmas are not.
Explanation:
Without doing any calculations, arrange the elements in CF2Cl2 in order of decreasing mass percent composition. Rank from highest percent to lowest.
a. C > F > Cl
b. F < Cl > C
c. Cl > C > F
d. Cl > F > C
Answer:
a. C > F > Cl
Explanation:
We know that atomic mass of Chlorine is greater than of Florine than that of carbon. Moreover, in CF2Cl2, therefore, there are two atoms of Cl, F and one atom of C. Therefore, in CF2Cl2 in order of decreasing mass percent composition C > F > Cl. Therefore, the correct option is a.
what is the chemical symbol and name of the third element in the periodic table
Answer: Aluminum symbol Al or aluminum American English
Explanation:
Answer:
Hii
Li( Lithium)
Explanation:
Lithium has the atomic number of three and is the third element in periodic table.
Determine the limiting reactant in a mixture containing 95.7 g of B2O3, 75.7 g of C, and 369 g of Cl2. Calculate the maximum mass (in grams) of boron trichloride, BCl3, that can be produced in the reaction. The limiting reactant is:
Answer:
[tex]B_2O_3[/tex]
Explanation:
First, we have to find the reaction:
[tex]B_2O_3~+~C~+~Cl_2~->~BCl_3~+~CO[/tex]
The next step is to balance the reaction:
[tex]B_2O_3~+~3C~+~3Cl_2~->~2BCl_3~+~3CO[/tex]
Now, we have to calculate the molar mass for each compound, so:
[tex]B_2O_3=~69.62~g/mol[/tex]
[tex]C=~12~g/mol[/tex]
[tex]Cl_2=~70.96~g/mol[/tex]
With these values, we can calculate the moles of each compound:
[tex]95.7~g~B_2O_3\frac{1~mol~B_2O_3}{69.62~g~B_2O_3}=1.37~mol~B_2O_3[/tex]
[tex]75.7~g~C\frac{1~mol~C}{112~g~C}=6.30~mol~C[/tex]
[tex]369~g~Cl_2\frac{1~mol~Cl_2}{70.96~g~C}=5.20~mol~Cl_2[/tex]
Now we can divide by the coefficient of each compound in the balanced equation:
[tex]\frac{1.37~mol~B_2O_3}{1}=~1.37[/tex]
[tex]\frac{6.30~mol~C}{3}=~2.1[/tex]
[tex]\frac{5.20~mol~Cl_2}{3}=~1.73[/tex]
The smallest values are for [tex]B_2O_3[/tex], so this is our limiting reagent.
I hope it heps!
Select the correct answer. What is heat of vaporization?
A. It is the heat required to change a substances temperature by 1C
B. It is the heat required to change a gram of substance from a solid to a liquid
C. It is the heat required to change a substance from a solid directly to a gas
D. It is the heat required to change a gram of substance from a liquid to a gas
E. It is the heat required to separate one substance into two substances
Answer:
D) it is the heat required to change a gram of substance from a liquid to a gas
Explanation:
idk i think its correct but if its wrong just let me know
The temperature program for a separation starts at a temperature of 50 °C and ramps the temperature up to 270 °C at a rate of 10 °C/minute. Which statement is NOT true for this separation?
A) At 10 °C/minute, a total of 22 minutes is needed to reach 270 oC.
B) Strongly retained solutes will remain at the head of the column while the temperature is low.
C) Weakly retained solutes will separate and elute early in the separation.
D) The vapor pressure of strongly retained solutes will increase as temperature increases.
E) Strongly retained analytes will give broad peaks.
Answer:
The correct answer to the question is Option E (Strongly retained analytes will give broad peaks).
Explanation:
The other options are true because:
A. Initial temp = 50 °C
Final temp = 270 °C
Differences in temp = 270 - 50 = 220°C
Rate = 10 °C/minute.
So, at 10 °C/minute,
total of 220°C /10 °C = number of minutes required to reach the final temp.
220/10 = 22 minutes
B. A column has a minimum and maximum use temperature. Solutes that are already retained would remain stationary while temperatures are low. This would only change if there is an increase in temperature. Heat transfers more energy to the liquid which would make the solute interact with the column phase.
C. Weakly retained solutes may contain larger molecules, will separate by absorbing into the solvent early in separation making the mobile phase separates out into its components on the stationary phase.
D. Retained solute's vapor pressure is higher at higher temperatures making it possible for particle to escape more from the solute when the temperature is high than when it is low.
Empirical formula for compound of 2.17 mol N and 4.35 mol O
Answer:
Explanation:
ratio of moles of N and O in molecule =
N / O = 2.17 / 4.35
1/2
empirical formula = NO₂
Which of these statements gives a correct reason as to why our body needs water?
(1 Point)
1. It provides us with energy.
2. It helps us to eliminate waste.
3. It helps regulate our body temperature.
Answer:
2. It helps us to eliminate waste
3. It helps regulate our body temperature
Explanation:
In addition to the function of bringing nutrients to the cells, water provides the elimination of substances out of the body. This occurs, for example, through urine, which is basically formed by water and toxic or excess substances dissolved.
Water also helps in regulating body temperature. This occurs when the heat becomes exaggerated, sweat is released, which has water in its composition. When in contact with the medium, the sweat evaporates on the surface of the skin, causing the body to cool.
The boiling point of diethyl ether, CH3CH2OCH2CH3, is 34.500 °C at 1 atmosphere. Kb(diethyl ether) = 2.02 °C/m In a laboratory experiment, students synthesized a new compound and found that when 14.94 grams of the compound were dissolved in 279.5 grams of diethyl ether, the solution began to boil at 35.100 °C. The compound was also found to be nonvolatile and a non-electrolyte. What is the molecular weight they determined for this compound ?
Answer:
The correct answer is 179.94 g/mol.
Explanation:
Based on the given question, the boiling point of diethyl ether us 34.500 degree C at 1 atm pressure. The boiling point of the solution given is 35.100 degree C. The Kb of diethyl ether given is 2.02 degree C/m. The weight of the compound given is 14.94 grams, the weight of the solvent (diethyl ether) is 279.5 grams.
The molecular weight of the compound can be determined by using the formula,
deltaTb = Kb * molality
Tb-To = Kb * molality
Tb-To = Kb*wt/mol.wt*1000/w (solvent)
35.100 - 34.500 = 2.02 * 14.94 / mol. wt * 1000 g / 279.5 g
0.6 = 2.02 * 53.45/ mol.wt
mol. wt = 2.02*53.45/0.6
mol. wt = 179.94 g/mol
Hence, the molecular weight of the compound is 179.94 gram per mol.
What happens in a neutralization reaction?
a
The hydrogen (H+) ions from the base and the hydroxide (OH-) ions from the acld come together to form water.
The hydrogen (H+) ions from the acid and the hydroxide (OH) ions from the base come together to form water.
A substance's pH is increased to a value greater than 7.
A solution of a known concentration and volume is added until the reaction is completed.
Answer:
Answer is letter B
Explanation:
The first one is wrong because acids release H+, not bases.
The third one is wrong because the pH is exactly 7, not greater.
The last one is wrong because it is vague and does not fit a neutralization reaction.
The wolf gets enegry from____
The rabbit gets energy from____
The plant gets energy from___
The mushoom gets energy from___
Answer:
The wolf gets energy from other Animals through Cellular respiration. it's a carnivore
The rabbit gets energy from Carbohydrates,Fats.... obtained through different sources. A common example is the grass. It's an herbivore
The plant gets energy from the sun during photosynthesis. It's Autotrophic.
The mushroom gets energy from the decomposition of other organic matter. It's heterotrophic.
Explanation:
In a food chain; The Wolf eats the rabbit, when the Wolf dies, decomposers such as mushrooms breaks down its body returning it to the soil, where it provides nutrients for plants
In the Lewis structure of an ozone molecule, we saw that it is made of three oxygen atoms, and the central atom is connected to the other two oxygen atoms with equivalent bonds. It turns out that the ozone molecule has a small dipole moment. How is it possible, given that all the atoms are the same
Answer:
Ozone has dipole moments because its molecular chemical structure is no linear.
Explanation:
This molecular form refers to the geometry of said gas, which is potentially toxic and dangerous.
This non-linear geometric shape is what makes it have dipolarity.
Classify an element having the following ground state electron configuration as an alkali metal, alkaline earth metal, nonmetal, halogen, transition metal, or noble gas.
a. [Ne]3s1
b. [Ne]3s23p3
c. [Ar]4s23d104p5
d. [Kr]5s24d1
e. [Kr]5s24d105p6
Explanation:
Alkali metal refers to group1 elements.
Alkali earth metal refers to group 2 elements.
Non metals refers to elements in grouos 4 to group 7.
Halogen refers to group 17 elements
Transition Metal refers to group 3 to group 12 elements
Noble gases refer to elements in group 18.
To obtain the group number from the electronic configuration, we calculate the total number of electrons in the principal quantum number (coefficient of the letters).
a. [Ne]3s1
Principal quantum number = 3
Number of electrons present = 1
This element belongs to group 1. It is an Alkali Metal.
b. [Ne]3s23p3
Principal quantum number = 3
Number of electrons present = 2 + 3 = 5
This element belongs to group 15 (5A). It is a Non metal
c. [Ar]4s23d104p5
Principal quantum number = 4
Number of electrons present = 2 + 5 = 7
This element belongs to group 17 (7A). It is an Halogen.
d. [Kr]5s24d1
This configuration belongs to the element yttrium and has an incomplete d shell. Hence it is a transition metal.
e. [Kr]5s24d105p6
Principal quantum number = 5
Number of electrons present = 2 + 6 = 8
This element belongs to group 18 (8A). It is a Noble gas.
One of the radioactive isotopes used in chemical and medical research is sulfur-35, which has a half-life of 87 days. How long would it take for 0.25 g to remain of a 1.00 g sample of sulfur-35
Answer:
Time taken = 174 days
Explanation:
Half life is the time take for a subsrtance taken to decay to half of it's origial or initial concentration.
In this probel, the haf life is 87 days, this means that after evry 87 days, the concentration or mass of sulfur-35 decreases by half.
If the starting mass is 1.00g, then we have;
1.00g --> 0.5g (First Half life)
0.5g --> 0.25g (Second half life)
This means that sulphur-335 would undergo two half lives for 0.25g to remain.
Total time taken = Number of half lives * Half life
Time taken = 2 * 87
Time taken = 174 days
Arrange the measurements from least to greatest
Answer: 1.8 micrograms, 1.8 milligrams, 1.8 grams, 1.8 kilograms
Explanation:
consider an exceptionally weak acid, HA, with Ka= 1 x 10-20. you make 0.1M solution of the salt NA. what is the pH.
Answer:
[tex]pH=10.5[/tex]
Explanation:
Hello,
In this case, the dissociation of the given weak acid is:
[tex]HA\rightleftharpoons H^++A^-[/tex]
Therefore, the law of mass action for it turns out:
[tex]Ka=\frac{[H^+][A^-]}{[HA]}[/tex]
That in terms of the change [tex]x[/tex] due to the reaction extent is:
[tex]1x10^{-23}=\frac{x*x}{0.1-x}[/tex]
Thus, by solving with the quadratic equation or solver, we obtain:
[tex]x=31.6x10^{-12}M[/tex]
Which clearly matches with the hydrogen concentration in the solution, therefore, the pH is:
[tex]pH=-log(-31.6x10^{-12})\\pH=10.5[/tex]
Regards.
Which of the following is a property of matter?
The major properties of matter are volume, mass, and shape.
All matter however too is made up of tiny particles known as atoms.
Other characteristics properties of matter which can be measured include object's density, color, length, malleability, melting point, hardness, odor, temperature, and others
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The property of matter should be volume, mass, and shape.
The following information should be considered:
The matter should be made up of small & tiny particles that we called as the atoms. It involved the density of an object, length, temperature, melting point, etc.Learn more: https://brainly.com/question/1979431?referrer=searchResults
Which of the following formulas represents an ionic compound?
1.HI 2.HCI 3.LiCI 4.SO2
Answer:
Numbers 4,3
Explanation:
Ionic bond is between nonmental and metals
A sample of chemical X is found to contain 5.0 grams of oxygen, 10.0 grams of carbon, and 20.0 grams of nitrogen. The law of definite proportion would predict that a 75 gram sample of chemical X should contain how many grams of carbon
Answer: 75 grams sample of chemical X should contain 21.43 grams of carbon
Explanation: The law of definite proportion states that a given chemical compound always contains its component elements in fixed ratio.
From the question, chemical X contains 5.0 grams of oxygen, 10.0 grams of carbon, and 20.0 grams of nitrogen.
Sum up the masses
5.0g + 10.0g + 20.0g = 35.0g
This means, 10.0 grams of carbon are present in 35.0 grams of chemical X.
Now, to the determine the mass of carbon that 75 gram sample of chemical X should contain,
According to the law of definite proportion, the component elements of a given chemical compound are in fixed ratio. Therefore,
If 35.0g of chemical X contains 10.0g of carbon
Then, 75 g of chemical X will contain
(75 × 10) / 35 g
= 21.43 grams
Hence, 75 grams sample of chemical X should contain 21.43 grams of carbon.
Answer:
According to the law of definite proportion, a 75 gram sample of chemical X should contain 21.249 grams of carbon.
Explanation:
The total mass of the sample is equal to the sum of masses of oxygen, carbon and nitrogen. That is:
[tex]m_{tot} = m_{O} + m_{C} + m_{N}[/tex]
If [tex]m_{O} = 5\,g[/tex], [tex]m_{C} = 10\,g[/tex] and [tex]m_{N} = 20\,g[/tex], then:
[tex]m_{tot} = 35\,g[/tex]
According to the law of definite proportion, the following simple rule of three is used:
[tex]m_{C'} = m_{C} \times \frac{m_{tot'}}{m_{tot}}[/tex]
If [tex]m_{C} = 10\,g[/tex], [tex]m_{tot} = 35\,g[/tex] and [tex]m_{tot'} = 75\,g[/tex], then:
[tex]m_{C'} = 10\,g\times \frac{75\,g}{35\,g}[/tex]
[tex]m_{C'} = 21.429\,g[/tex]
According to the law of definite proportion, a 75 gram sample of chemical X should contain 21.249 grams of carbon.
Suppose the amount of a certain radioactive substance in a sample decays from to over a period of days. Calculate the half life of the substance. Round your answer to significant digit.
The given question is incomplete, the complete question is:
Suppose the amount of a certain radioactive substance in a sample decays from 1.30 mg to 100. ug over a period of 29.5 days. Calculate the half life of the substance Round your answer to 2 significant digits.
Answer:
The correct answer is 7.974 days.
Explanation:
Based on the given question, the concentration of a radioactive substance present in a sample get decays to 100 micro grams from 1.30 milligrams in 29.5 days. There is a need to find the half-life of the substance.
Radioactive decay is an illustration of first order reaction.
K = (2.303 / t) log [a/(a-x)]
Here a is 1.30 mg and (a-x) is 100 micrograms = 100 * 10^-3 mg or 0.1 mg, and t is 29.5 days. Now putting the values we get,
K = (2.303 /29.5)log (1.30/0.1)
= 2.303/29.5 log13
= 2.303/29.5 * 1.1139
K = 0.0869
The half-life or t1/2 is calculated by using the formula, 0.693 / K
= 0.693 / 0.0869
= 7.974 days.
Two hypothetical ionic compounds are discovered with the chemical formulas XCl2 and YCl2, where X and Y represent symbols of the imaginary elements. Chemical analysis of the two compounds reveals that 0.25 mol XCl2 has a mass of 100.0 g and 0.50 mol YCl2 has a mass of 125.0 g. (a) What are the molar masses of XCl2 and YCl2
Answer:
THE MOLAR MASS OF XCL2 IS 400 g/mol
THE MOLAR MASS OF YCL2 IS 250 g/mol.
Explanation:
We calculate the molar mass of XCL2 and YCL2 by bringing to mind the formula for molar mass when mass and amount or number of moles of the substance is given.
Number of moles = mass / molar mass
Molar mass = mass / number of moles.
For XCL2,
mass = 100 g
number of mole = 0.25 mol
So therefore, molar mass = mass / number of moles
Molar mass = 100 g / 0.25 mol
Molar mass = 400 g/mol.
For YCL2,
mass = 125 g
number of mole = 0.50 mol
Molar mass = 125 g / 0.50 mol
Molar mass = 250 g/mol.
So therefore, the molar mass of XCL2 and YCL2 IS 400 g/mol and 250 g/mol respectively.
You add 5.7 g of iron to 25.20ml of water and observe that the volume of the iron and water together is 25.92ml calculate thw density of the iron
Answer:
7.92gml-1
Explanation:
water=25.20ml
water+iron=25.92ml
iron=5.7g
P=mass/volume (formula of density)
mass=5.7g
volume=25.92-25.20
=0.72ml
p=5.7/0.72
=7.92gml-1
Given:
Initial volume of water = 25.20mL
Volume of water after iron is added = 25.92mL
Mass of iron = 5.7g
So, the volume of iron = 25.92mL - 25.20mL = 0.72mL
∴ Density of iron will be
Density = Mass/Volume
Density = 5.7g / 0.72mL
Density = 7.91 g/mL
What is density in short answer?
The density of a substance is the relationship between its mass and how much space it takes up. Density equals the mass of the substance divided by its volume, D = m/v.
What is the SI unit of density?Though SI unit of density is kg/m³ solids, g/ml for liquids and g/L for gases.
Learn more about Density here
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