Answer:
7 mol
Explanation:
Caffeine molecular formula C8H10N4O2. It has 2 atoms of oxygen.
C8H10N4O2 - 2O
1 mol 2 mol
3.5 mol x mol
x = 3.5*2/1 = 7 mol
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.
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
Suppose you were preparing 1.0 L of a bleaching solution in a volumetric flask, and it calls for 0.21 mol of NaOCl. If all you had available was a jug of bleach that contained 0.78 M NaOCl, what volume of bleach would you need to add to the volumetric flask before you added enough water to reach the 1.0 L line
Answer: brainliesss plssssssss
0.256 L
Explanation:
We should use the following formula:
concentration (1) × volume (1) = concentration (2) × volume (2)
concentration (1) = 0.82 M NaOCl
volume (1) = ?
concentration (2) = 0.21 M NaOCl
volume (2) = 1 L
volume (1) = [concentration (2) × volume (2)] / concentration (1)
volume (1) = [0.21 / 1] / 0.82 = 0.256 L
What is the name of this molecule? (will give BRAINLIEST)
A straight chain of four carbons. There is a triple bond between the second and third carbons when counting from left to right or right to left.
Answer:
2 - Butyne
Explanation:
The name of the molecule with a carbon atoms arranged in a straight chain with a triple bond between the second and third carbons is 2 - Butyne.
2- Butyne is an alkyne with structural formula given below. Some of the properties of Butyne include it is a produced artificially, it is volatile and colorless in nature.
Hence, the given molecules described is 2 - Butyne.
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.
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
Catalysts are substances that increase the rate of reaction but can be recovered unchanged at the end of the reaction. Catalysts can be classified as either homogeneous (same state as reactants) or heterogeneous (different state than reactants).
Platinum is used to catalyze the hydrogenation of ethylene:
H2(g)+CH2CH2(g)−⟶Pt(s)CH3CH3(g)
Chlorofluorocarbons (CFCs) catalyze the conversion of ozone (O3) to oxygen gas (O2):
2O3(g)−⟶CFC(g)3O2(g)
Magnesium catalyzes the disproportionation of hydrogen peroxide to produce water and oxygen:
2H2O2(aq)−⟶Mg(s)2H2O(l)+O2(g)
What type of catalysts are platinum, CFCs, and magnesium under these conditions?
Answer:
- Platinum acts as a heterogeneous catalyst in the hydrogenation of ethylene.
- CFCs act as homogeneous catalysts in the conversion of ozone to oxygen gas.
- Magnesium acts as a heterogeneous catalyst in the disproportionantion of hydrogen peroxide.
Explanation:
Hello,
For the given reactions, considering the definition of homogeneous and heterogeneous catalyst, we can identify that is each catalyst behave as follows:
- Platinum acts as a heterogeneous catalyst in the hydrogenation of ethylene as all the reactants are gaseous but it remains solid.
- CFCs act as homogeneous catalysts in the conversion of ozone to oxygen gas as it remains gaseous as well as both ozone and oxygen.
- Magnesium acts as a heterogeneous catalyst in the disproportionantion of hydrogen peroxide as it is solid whereas the other species are aqueous, liquid and gaseous
Best regards.
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.
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.
A structural model of retinol is shown below. How many hydrogen atoms are
in retinol?
HC CHS
H3C
H3c
"OH
CH
A. 30
B. 23
C. 16
D. 26
Answer:
A. 30
Explanation:
Retinol is the chemical form of Vitamin A. It has a chemical formula of C20H30O.
It is processed when retinyl palmitate is broken down in the small intestine. Retinol helps in the proper regulation of eye cells hence a vital component in ensuring good eye sight.
It also helps in the neutralization of free radicals in the body and acts as an antioxidant which prevents cells of the body from ageing.
Wax melts when it is heated which most likely describes what is true of the result of this reaction
Answer:
Was is a hydrocarbon therefore when heated some co2 escapes but later solidifies
Explanation:
Hope it helps
3. Are all amino acids are chiral? Why or why not? Protein only contain ____ (L-/D-) amino acids. Which organic molecule is the standard molecule for L-/D- configuration system? The chiral carbon in L-Alanine is ______ (R- /S-) configuration, but in D-Alanine is ________ (R-/S-) configuration.
Answer:
Protein are essential in body cells for the repair of worn out tissues. Amino acid is gotten when protein is broken down under certain conditions.
All amino acids are chiral with the exception of glycine. This means they have a central carbon atom with the R-, -COOH, and -NH2 group attached to it.
Protein contain only L amino acid because the L amino acid is the only type used by cells.
The chiral carbon in L-Alanine is S-configuration and D-Alanine is R-configuration.
Select the correct answer.
What effect does an increase in products have on the reaction rate of a mixture at equilibrium?
A.
The forward reaction rate increases.
B.
Both the forward and the reverse reaction rates decrease.
Both the forward and the reverse reaction rates increase.
D.
The reverse reaction rate increases.
Reset
Next
Answer:
At equilibrium the rate of the forward reaction is equal to the rate of the backward reaction.
When the product of a reaction at equilibrium is increased the equilibrium will shift left or to the reactant side. As a result the excess product will get converted to reactant. This is in accordance to Le Chatelier's principle.
Le Chatelier's principle states that when a system is subjected to stress the equilibrium will shift in a direction to minimize effect of the stress.
Thus the products added to the system at equilibrium will make the equilibrium shift to the reactant side, the rate of the reverse or backward reaction will increase.
Explanation:
Hope This Helps Amigo!
The molar enthalpy of
mole of a liquid.
is the heat required to vaporize one
thermochemical equation
combustion
released
vaporization
fusion
absorbed
heat
Answer:
vaporization
Explanation:
The molar enthapy of _vaporization______ is the heat required to vaporize one mole of a liquid”
A 1.44 L buffer solution consists of 0.137 M butanoic acid and 0.275 M sodium butanoate. Calculate the pH of the solution following the addition of 0.069 moles of NaOH . Assume that any contribution of the NaOH to the volume of the solution is negligible. The Ka of butanoic acid is 1.52×10−5 .
Answer:
The answer is "[tex]P^{H}=5.379[/tex]".
Explanation:
[tex]\ NaOH \ value = \frac{n}{v}\\\\[/tex]
[tex]=\frac{0.069\ moles}{0.144L}\\\\=0.04791\ M[/tex]
[tex]\ Ka=1.52 \times 10^{-5}\\\\P^{ka} = -10g \ ka \\\\[/tex]
[tex]= -10 \times 1.52 \times 10^{-5}\\\\= 4.82\\[/tex]
Equation:
[tex]CH_3CH_2CH2COOH+NaOH\rightarrow CH_3CH_2CH_2COONa +H_2O\\\\[/tex]
[tex]\boxed{\left\begin{array}{ccccc}I &0.137 &0.04791 &0.275 & -- \\ C &-0.04791 &-0.04791 &+0.04791 & -- \\E &0.08909 &0&0.32291 & -- \end{array}\right}[/tex]
[tex]P^{H}= P^{ka}+\log\frac{CH_3CH_2CH_2COONa}{CH_3CH_2CH_2COOH}\\\\[/tex]
[tex]= 4.82+\log\frac{0.32291}{0.08909}\\\\=5.379[/tex]
An attempt at synthesizing a certain optically active compound resulted in a mixture of its enantiomers. The mixture had an observed specific rotation of 14.1°. If it is known that the specific rotation of the R enantiomer is –28.4°, determine the percentage of each isomer in the mixture. g
Answer:
The percentage of the R-enantiomer is 26.18% while the percentage of the S-enantiomer is 73.82%
Explanation:
If the specific rotation of R enantiomer = -28.4, then the specific rotation of S = +28.4
Now, let us have x = % R, thus
% S = 100-x =y
Hence;
{- 28.4x + 28.4( 100 -x)}/100= 14.1
Thus;
-28.4x + 2840 -28.4x = 1410
-56.8x + 2840 = 1410
-56.8x = 1410-2840
-56.8x = -1430
x = 1430/56.8
x = 26.18%
y = 100-26.18% = 73.82%
How is the mass of the atom calculated?
by adding the number of protons and electrons
by adding the number of protons and neutrons
by subtracting the number of electrons from the number of protons
by adding the number of neutrons and electrons
The mass of the atom is calculated by adding the number of protons and neutrons .
What do you mean by atomic mass of an element ?The total mass of one atom of an element is defined as its atomic mass. The atomic mass is taken as the mass of protons and neutrons in an atom.
1 a m u = 1.66 ×10⁻²⁴g
To calculate the atomic mass of an element -:
The atomic mass of the single atom can be calculated by adding the total number of protons and the total number of neutrons of that particular atom.
Atomic mass Number = Number of protons + number of neutrons
Hence ,in this way the atomic mass is calculated of an atom .
Learn more about atomic mass ,here:
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what are mineralocorticoids
Explanation:
it is used to describe those action of adrenal corticosteroids that produce sodium
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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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
4 molecules of glucose has how many carbon hydrogen and oxygen
Answer:
24 carbons
48 hydrogens
24 oxygen
Explanation:
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.
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.
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.
In this reaction: Mg (s) + I₂ (s) → MgI₂ (s)
If 2.34 moles of Mg react with 3.56 moles of I₂, and 1.76 moles of MgI₂ form, what is the percent yield?
Answer:
98.9%
Explanation:
2 moles of I₂ are required for each mole of Mg, so the reaction is limited by the available I₂. The 3.56 moles of I₂ should react with 1.78 moles of Mg to produce 1.78 moles of MgI₂. Instead, we get 1.76 moles of MgI₂.
The yield is 1.76/1.78 × 100% ≈ 98.876%
The yield is 98.9% of the quantity expected based on available reactants.
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
rinking water suggest an upper limit of 250 mg/L for chloride ion. If 1.03×104 liters of water in a storage tank contains 1.40 grams of Cl-, what is the contaminant level in ppm? in ppb? Is this level acceptable based on EPA guidelines?
Answer:
This water has a level acceptable, 0.1359ppm and 135.9ppb.
Explanation:
1.40g of Cl⁻ are:
1.40g Cl⁻ × (1000mg / 1g) = 1400mg Cl⁻
In 1.03x10⁴L:
1400mg / 1.03x10⁴L = 0.1359mg/L.
As the upper limit of Cl⁻ in water is 250mg/L, this water has a level acceptable
ppm are the ratio between mg of solute and liters of solution, that means the tank contains 0.1359mg/L = 0.1359ppm
ppb, parts per billion are 1000 times ppm, thus, parts per billion of the storage tank are:
0.1359ppm × 1000 = 135.9ppb
Arrange the measurements from least to greatest
Answer: 1.8 micrograms, 1.8 milligrams, 1.8 grams, 1.8 kilograms
Explanation:
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.