The reason we should store phosphorous in water is because it will ignite on contact with air
The oxide of element X is reduced by heating with carbon.Element X does not react with cold water, steam or dilute hydrochloric acid.What is X?
The question is incomplete, the complete question is;
The oxide of element X is reduced by heating with carbon.
Element X does not react with cold water, steam or dilute hydrochloric acid.
What is X?
A copper
B iron
C magnesium
D zinc
Answer:
Copper
Explanation:
Copper is below hydrogen in the activity series of metals. Remember that the activity series of metals is an arrangement of metals in order of decreasing reactivity from most reactive to least reactive. The metals at the head of the series are highly reactive, metals at the middle of the series are moderately reactive while metals below hydrogen in the series are least reactive.
Copper being below hydrogen in the series cannot displace it from water (cold or steam) or from dilute acid solutions. Copper can be reduced by heating it with carbon (thermal reduction).
8. A 65.0 mL 0.513 mol/l solution of glucose (C6H1206) was mixed with 125.0 mL of
2.33 mol/l glucose solution. What is the molar concentration of the final solution?
Assume the volumes are additive. The molar mass of glucose is 180 g/mol (10
points)
Answer:
The molar concentration of the final solution is 1.71 [tex]\frac{moles}{liter}[/tex]
Explanation:
Molarity is a way of expressing the concentration of solutions and indicates the number of moles of solute dissolved per liter of solution.
The molarity of a solution is calculated by dividing the moles of the solute by the volume of the solution.:
[tex]Molarity (M)=\frac{number of moles of solute}{volume}[/tex]
Molarity is expressed in units ([tex]\frac{moles}{liter}[/tex]).
Then, the number of moles of solute can be calculated as:
number of moles of solute= molarity* volume
So, in this case, the final concentration can be calculated as:
[tex]Final molarity (M)=\frac{Total number of moles of solute}{Total volume}[/tex]
where, being 65 mL=0.065 L, 125 mL=0.125 L and 190 mL=0.190 L (because 1000 mL= 1 L):
Total number of moles of solute= 0.065 L*0.513 [tex]\frac{moles}{liter}[/tex] + 0.125 L*2.33 [tex]\frac{moles}{liter}[/tex]= 0.033345 moles + 0.29125 moles= 0.324595 molesTotal volume= 65 mL + 125 mL= 190 mL= 0.190 LReplacing:
[tex]Final molarity (M)=\frac{0.324595 moles}{0.190 L}[/tex]
Final molarity ≅ 1.71 [tex]\frac{moles}{liter}[/tex]
The molar concentration of the final solution is 1.71 [tex]\frac{moles}{liter}[/tex]
1. 7.85 g of sodium metal is added to 200 mL of 0.0450 M HNO3
a) Predict the mass of the precipitate
b) Predict the amount of excess reagent left over
c) Volume of gaseous product at STP conditions
Answer:
a)0.765 g
b)7.613 g
c)0.20 L
Explanation:
Consider the reaction involved;
Na(s) + HNO3(aq) ----> NaNO3(s) + H2(g)
Note that, if a hot, saturated aqueous solution of sodium nitrate was allowed to cool, solid sodium nitrate would crystallise out of the solution and this would also be classed as a precipitate. This is the case here.
Number of moles of sodium reacted= mass of sodium reacted/ molar mass of sodium
Number of moles of sodium= 7.85g/23gmol-1
Number of moles of sodium= 0.34 moles of sodium
Number of moles of acid reacted= concentration of acid × volume of acid
Number of moles of acid= 0.0450 × 200/1000
Number of moles of acid= 9×10^-3 moles
Therefore, HNO3 is the limiting reactant.
1 mole of HNO3 yield 1 mole of NaNO3
9×10^-3 moles of HNO3 yield 9×10^-3 moles of NaNO3
Hence mass of NaNO3= number of moles × molar mass
Mass of NaNO3= 9.0×10^-3 moles × 84.9947 g/mol
Mass of NaNO3= 0.765 g of NaNO3
b)
Since
1 mole of sodium metal reacts with 1 mole of HNO3
9×10^-3 moles of sodium reacts with 9×10^-3 moles of HNO3
Therefore amount of unreacted sodium metal = 0.34 moles - 9×10^-3 moles = 0.331 moles
Mass of unreacted sodium metal = 0.331 moles × 23 gmol-1= 7.613 g
c)
If 1 mole of HNO3 yields 1 mole of hydrogen gas
9×10^-3 moles of HNO3 yields 9×10^-3 moles of hydrogen gas.
1 mole of hydrogen gas occupies 22.4 L
9×10^-3 moles of hydrogen gas will occupy 9×10^-3 moles × 22.4/1 = 0.20 L
Identify this molecule
Answer:
Ribose
Explanation:
This is the pentose sugar found in RNA commonly.
1. If the potassium hydrogen phthalate is not completely dry, how would it affect the reported molar concentration (molarity) of the NaOH solution in Part A? Explain.
The given question is incomplete. The complete question is as follows.
Pure potassiom hydrogen phthalate is used for standardization of the sodium hydroxide solution. Suppose that the potassium hydrogen phthalate is not completely dry. Will the reported molar concentration of the sodium hydroxide solution be too high, too low, or unaffected because of the moistness of the potassium hydrogen phthalate? Explain please.
Explanation:
When potassium hydrogen phthalate is not completely dry then it means there will be some water present in it. According to this, actual potassium hydrogen phthalate is diluted because of the presence of water molecules.
Hence, 1 mole of potassium hydrogen phthalate needs 1 mole of NaOH. And, at the equivalence point according to the concept of moles:
No. of moles of potassium hydrogen phthalate = No. of moles of NaOH
Also, the titration of potassium hydrogen phthalate concentration is less because of the presence of water then the number of moles of NaOH calculated will be less.
Thus, we can conclude that the molar concentration of the sodium hydroxide solution be too low.
Which list of elements contains a metal, a metalloid,a nonmetal, and a noble gas
Answer:
sodium, silicon, and argon
Explanation:
castle learning
1). Calculate the mass of hydrogen peroxide needed to obtain 0.460 L of oxygen gas at STP
2H2O2(aq) → 2H2O(l) + O2(g)
2) 1. Use the reaction shown to calculate the mass of iron that must be used to obtain 0.500 L of hydrogen at STP.
3Fe(s) + 4H2O(l) → Fe3O4(s) + 4H2(g)
Answer:
1) 1.39 grams H2O2
2) 0.933 grams Fe
Explanation:
Step 1: Data given
Volume of oxygen = 0.460 L
STP = 1 atm and 273 K
Step 2: The balanced equation
2H2O2(aq) → 2H2O(l) + O2(g)
Step 3: Calculate the number of moles O2
p*V = n*R*T
⇒with p= the pressure = 1 atm
⇒with V = the volume = 0.460 L
⇒with n = the number of moles = TO BE DETERMINED
⇒with R = the gas constant = 0.08206 L*atm/mol*K
⇒with T = the temperature = 273 K
n = (p*V)/(R*T)
n = (1 * 0.460)/ (0.08206*273)
n = 0.0205 moles moles
Step 4: Calculate moles H2O2
For 2 moles H2O we'll have 2 moles H2O and 1 mol O2
For 0.0205 moles O2 we'll need 2*0.0205 = 0.041 moles H2O2
Step 5: Calculate mass H2O2
Mass H2O2 = moles H2O2 * molar mass H2O2
Mass H2O2 = 0.041 moles * 34.01 g/mol
Mass H2O2 = 1.39 grams
Step 1: Data given
Volume of hydrogen = 0.500 L
STP = 1 atm and 273 K
Step 2: The balanced equation
3Fe(s) + 4H2O(l) → Fe3O4(s) + 4H2(g)
Step 3: Calculate the moles of H2
p**V = n*R*T
⇒with p= the pressure = 1 atm
⇒with V = the volume = 0.500 L
⇒with n = the number of moles = TO BE DETERMINED
⇒with R = the gas constant = 0.08206 L*atm/mol*K
⇒with T = the temperature = 273 K
n = (p*V) / '*T)
n = (1 * 0.500) / (0.08206 * 273)
n = 0.0223 moles
Step 4: Calculate moles Fe
For 3 moles Fe we need 4 moles H2O to produce 1 mol Fe3O4 and 4 moles H2
For 0.0223 moles H2 we'll need 0.0223 *3/4 = 0.0167 moles Fe
Step 5: Calculate mass of Fe
Mass Fe = moles Fe * atomic mass Fe
Mass Fe = 0.0167 moles * 55.845 g/mol
Mass Fe = 0.933 grams Fe
1. The mass of the hydrogen peroxide should be 1.39 grams H2O2.
2) The mass of the iron should be 0.933 grams Fe.
Calculation of the mass:Since
Volume of oxygen = 0.460 L
STP = 1 atm and 273 K
Now The balanced equation
2H2O2(aq) → 2H2O(l) + O2(g)
Now the number of moles O2
p*V = n*R*T
Here p= the pressure = 1 atm
V = the volume = 0.460 L
n = the number of moles = ?
R = the gas constant = 0.08206 L*atm/mol*K
T = the temperature = 273 K
Now
n = (p*V)/(R*T)
n = (1 * 0.460)/ (0.08206*273)
n = 0.0205 moles moles
Now moles H2O2 should be
For 2 moles H2O we'll have 2 moles H2O and 1 mol O2
So,
For 0.0205 moles O2 we'll need 2*0.0205 = 0.041 moles H2O2
Now mass H2O2
Mass H2O2 = moles H2O2 * molar mass H2O2
Mass H2O2 = 0.041 moles * 34.01 g/mol
Mass H2O2 = 1.39 grams
2. The mass of the iron should be
Since
Volume of hydrogen = 0.500 L
STP = 1 atm and 273 K
Now
The balanced equation
3Fe(s) + 4H2O(l) → Fe3O4(s) + 4H2(g)
Now the moles of H2
p**V = n*R*T
Here
p= the pressure = 1 atm
V = the volume = 0.500 L
n = the number of moles = ?
R = the gas constant = 0.08206 L*atm/mol*K
T = the temperature = 273 K
So,
n = (p*V) / '*T)
n = (1 * 0.500) / (0.08206 * 273)
n = 0.0223 moles
Now Calculate moles Fe
For 3 moles Fe we need 4 moles H2O to produce 1 mol Fe3O4 and 4 moles H2
So,
For 0.0223 moles H2 we'll need 0.0223 *3/4 = 0.0167 moles Fe
Now the mass of Fe
Mass Fe = moles Fe * atomic mass Fe
Mass Fe = 0.0167 moles * 55.845 g/mol
Mass Fe = 0.933 grams Fe
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In the following reaction, which are the products?
Mg + 2HCl —> H2 + MgCl2
If you could, please explain as well.
Answer: H2 + MgCl2
Explanation: As they are on the right side of the equation/ are the products being made as a result of the reaction, they are the products.
the vessel in which electrolysis takes place is called
PLEASE GUYS ANSWER IT
What systems need to be in place to ensure fairness in healthcare?
Answer:
The Healthcare system should be a welcome place to the different tiers of people in the society. There should be zero form of discriminations and everyone should be should be treated in the same way. Defaulters should be frowned at and adequate punishments should be meted out. There should be strict accountability of the funds made available to the healthcare centers to prevent diversion and any corrupt practices. These systems need to be in place to ensure fairness in healthcare.
what is an example of a soultion
Answer:
Did you mean solution??
In chemistry, a solution is considered as a special type of homogeneous mixture composed of two or more substances. In such a mixture, a solute is a substance dissolved in another substance, known as a solvent.
Eg: sweet tea or coffee (sugar added to solution)
bleach (sodium hypochlorite dissolved in water)
HOPE IT HELPS :)
If a gas at 35°C and 2.3 atm is heated to 50°C, then what will the new pressure be? (Gay Lussac's Law)
Remember to convert Celsius tempertature into Kelvin. (Take the Celsius values and add 273)
Answer:
THE NEW PRESSURE OF THE GAS AT 50 °C IS 2.41 atm.
Explanation:
Initial temperature = 35 °C = 35 + 273 K= 308 K
Final temperature = 50 °C =50 + 273 K = 323 K
Initial pressure = 2.3 atm
Final pressure = unknown
Using the combined gas equation to get the relationship between pressure and temperature for a given gas sample, we have;
P1 / T1 = P2 / T2
P2 = P1 T2 / T1
P2 = 2.3 * 323 / 308
P2 = 742.9 /308
P2 = 2.41 atm.
THE NEW PRESSURE IS 2.41 atm at 50 °C
How many grams of chlorine gas are needed to react with 3.5 liters of a 1.7 molar
potassium bromide solution?
Cl2 + 2 KBr - 2 KCl + Br2
Answer: 211.2 grams
Explanation:
To calculate the number of moles for given molarity, we use the equation:
[tex]\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution in L)}}[/tex] .....(1)
Molarity of [tex]KBr[/tex] solution = 1.7 M
Volume of solution = 3.5 L
Putting values in equation 1, we get:
[tex]1.7M=\frac{\text{Moles of}KBr}{3.5L}\\\\\text{Moles of }KBr=\{1.7mol/L\times 3.5L}=5.95moles[/tex]
The balanced chemical reaction is:
[tex]Cl_2+2KBr\rightarrow 2KCl+Br_2[/tex]
According to stoichiometry:
2 mole of KBr requires = 1 mole of [tex]Cl_2[/tex]
5.95 moles of KBr requires = [tex]\frac{1}{2}\times 5.95=2.975[/tex] moles of [tex]Cl_2[/tex]
Mass of [tex]Cl_2=moles\times {\text {Molar mass}}=2.975mol\times 71g/mol=211.2g[/tex]
Thus 211.2 grams of chlorine gas are needed to react with 3.5 liters of a 1.7 molar potassium bromide solution
D
Which word equation shows hydrogen reacting with oxygen to form water?
anygen - water - hydrogen
hydrogen-orbeneater
appudaplu...dk
und---- udaplu
explanation
the chemical formula of water is H²O.
Hydrogen+Oxygen=water
answer
Hydrogen-Water-Hydrogen
The sodium salt, NaA, of a weak acid is dissolved in water; no other substance is added. Which of these statements (to a close approximation) is true?
Answer:
Your question is somewhat poorly worded, even so what I can contribute is the statement is false, since the salt is sodium chloride, where its severe chemical formula NaCl, is a SALT not an acid and if it dissolves in water, seriously the solute of a solution, where water plays the role of the solvent
Explanation:
Sodium chloride is a binary salt, very easy to dissolve in water, it is also called the famous table salt, since it can be ingested in food even though it is not so recommended against high blood pressure conditions.
Consider the intermediate equations: 3 equations.
C(s) + O2(g) --> CO2(g) Delta H1 = -393.5 kJ
2CO(g) + O2(g) --> 2CO2(g) Delta H2 = -566.0 kJ
2H2O(g) --> 2H2(g) + O2(g) Delta H3 = 483.6 kJ
With the overall reaction:
C(s) + H2O(g) --> CO(g) + H2(g) Delta Hrxn = ?
QUESTION 1:
What must be done to calculate the enthalpy of reaction?
The first must be halved.
The first must be reversed.
The second must be halved.
The second must be reversed.
The third must be halved.
The third must be reversed.
QUESTION 2:
What is the overall enthalpy of reaction?
Delta Hrxn = ____ kJ
Answer:
C. The second equation must be halved
D. The second equation must be reversed
E. The third equation must be halved.
Delta Hrxn= 131.3 kJ
Explanation:
The correct answer is -582 KJ.
What is the enthalpy of reaction?
Enthalpy is the heat content of a system.The enthalpy change of a reaction is roughly equivalent to the amount of energy lost or gained during the reaction.A reaction is favored if the enthalpy of the system decreases over the reaction.What is the overall enthalpy of the reaction?
Equal to the sum of the standard enthalpies of the intermediate reaction steps is called overall enthalpyLearn more about enthalpy below,
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The United States consumes more oil per day than any other country. What would most likely happen to oil prices and availability worldwide if the United States were able to switch immediately to synfuels such as liquefied coal?
A. Oil prices would increase, and availability would increase. B. Oil prices would increase, and availability would decrease.
C. Oil prices would decrease, and availability would increase.
D. Oil prices would remain the same, and availability would increase.
E. Oil prices would remain the same, and availability would remain the same. PLEASE HURRY!!
Answer:
Oil prices would decrease, and availability would increase
Explanation:
Visit the interactive periodic table and locate the element neon (Ne). Use the information within the square to answer these questions.
Answer:
What is the atomic number of neon?
10
What is the atomic mass of neon? Give your answer to the nearest tenth.
20.2
The periodic table is a representation of the periodic elements based on atomic numbers. The atomic number of neon is 10, and the atomic mass is 20.2 amu.
What are the properties of neon?Neon is categorized as a stable gas that belongs to the noble gas group. It has been represented as Ne and is a monoatomic gas with no odor or color. It has an atomic number of 10 and an electronic configuration as, [He] 2s²2p⁶.
The atomic mass of neon elements is 20.2 amu and is said to have full electrons per shell. They do not need to donate or accept any electron as they have a balanced orbital. They have the property of fluorescence and are used in electric signs and lamps.
Therefore, neon is placed in group 18 and has atomic number 10 and a mass of 20.2 amu.
Learn more about neon, here:
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what a neat and well labelled diagram of nitrogen cycle in nature
Answer:
In the picture.
I hope it helps
Explanation:
Nitrogen cycle is a complex process (or sequence of reaction) by which nitrogen is removed and added to the soil.
Propenoic acid is an unsaturated carboxylic acid. Describe how you could show
that it is an unsaturated compound giving details of the test and the result.
Answer:
Tests for unsaturation involves addition across the multiple bonds in the unsaturated compound.
Explanation:
In organic chemistry, we define an unsaturated compound as any compound that contains a double or triple bond. These multiple bonds are also known as pi bonds.
There are two major tests for unsaturation which shall both be discussed here.
The first test for unsaturation is by the use of bromine water. The unknown sample is passed through a solution of bromine water which normally appears reddish brown. The bromine water becomes decolorized due to addition of bromine across the multiple bond. This is a standard test for unsaturation.
Secondly, unsaturated compounds decoulourize a solution of potassium permanganate when passed through it. This alone can not be used as a distinctive test for unsaturation.
Propenoic acid will give a positive test to the both reagents showing that it contains multiple bonds, in this particular instance, a double bond.
A 50.0 mL sample of 6.0 M HCl was diluted to a final volume of 250.0 mL What was the new molarity?
Answer:
1.2M
Explanation:
Initial Volume 0.05L
Final Volume 0.250L
HCl Molar mass: 36.46 g/mol
M = 6M HCl
Molarity = mol solute / L of solution
Inital M = Molarity = 6
mol solute = X = unknown
L of Solution = 0.05L
6 = X / 0.05
X = 0.3
X = 0.3/0.25
X = 1.2 M
There are ___________ forces of attraction between particles in the gas state. Use the following word bank to help you.
Answer:
Different
Explanation:
The correct answer is either a or d. Can anyone explain which one it is and why? CH3C ≡ CCH2CH2Cl is named: a. 1-chloro-3-pentyne b. 5-chloro-2-pentene c. 1-acetylenyl-3-chloropropane d. 5-chloro-2-pentyne
Answer: The IUPAC name of [tex]CH_3C\equiv CCH_2CH_2Cl[/tex] is 5-chloro-2-pentyne
Explanation:
1. First select the longest possible carbon chain. For the number of carbon atom, we add prefix as 'meth' for 1, 'eth' for 2, 'prop' for 3, 'but' for 4, 'pent' for 5, 'hex' for 6, 'sept' for 7, 'oct' for 8, 'nona' for 9 and 'deca' for 10.
2. The longest possible carbon chain should contain all the bonds and functional groups.
3. The numbering is done in such a way that the carbon containing the functional group or substituent gets the lowest number.
4. The naming of alkane is done by adding the suffix -ane, alkene by adding the suffix -ene, alkyne.
Thus the IUPAC name of [tex]CH_3C\equiv CCH_2CH_2Cl[/tex] is 5-chloro-2-pentyne
nvironmental Science
a.
Identify the biotic factor of an ecosystem from the following:
soil composition
b. trees
temperature
d. sunlight
C.
Answer:
c
Explanation:
Soil, Plants get energy from the sun.. Answer is C.
Answer:
B. trees
Explanation:
A biotic factor is something in an environment or ecosystem that is living. For example, plants and animals are biotic factors. An abiotic factor is just the opposite-they are not living. Rocks and water are examples of abiotic factors.
Soil composition, temperature and sunlight are all not alive. Therefore, they must be abiotic factors.
Trees are living organism. This means that they are biotic factors. So, the correct answer is B: trees.
Convert to standard notation.
8.127 x
10-4
Answer:
0.0008127
Explanation:
This is easy
Inorganic compounds which are found in the earth are called: minerals vitamins synthetics cement
Answer:
Minerals
Explanation:
I looked it up on google. Thanks.
What is the definition of acid ?
WILL MARK BRAINLIEST (if the answer is good and hasn't been copied from google and the first one who answer the question )
Answer:
Acid is a compound which dissolves in water to produce hydrogen ions (H+) and described as proton donors.
An invasive fish species was accidentally introduced into a river. At first, it experienced a sudden surge in its population. Then it experienced a steady decline. Which statements give plausible reasons for this trend?
Answer:
Correct Option is Option A
A.)It became prey to certain organisms in the river.
Explanation:
CHECK COMPLETE QUESTION BELOW;
An invasive fish species was accidentally introduced into a river. At first, it experienced a sudden surge in its population. Then it experienced a steady decline. Which statements give plausible reasons for this trend?
A.It became prey to certain organisms in the river.
B.It lacked adaptations suitable for that particular ecosystem.
C.It had no predators in its new environment.
D.It had few organisms to compete with for resources.
Aquatic invasive species are species such as fish or invertebrate that is absorbed by new aquatic environment that are differ from their own natural environment.
When Aquatic invasive species found themselves in a new environment, at first they will experience a rapid increase in the number of their population this is because of the lack of natural predators in the new aquatic environment. As a result of this they bring about the alteration of food web structure, they take in charge of available food for the native species and compete with them. As a result of this competition involved there is a decrease in the population.
Therefore, the statements that gives plausible reasons for this trend is that became prey to certain organisms in the river.
Answer:
It became prey to certain organisms in the river.
It lacked adaptations suitable for that particular ecosystem.
Explanation:
Took the test on Edmentum
If the pH of a solution is 9, the solution is A. acidic, which turns phenolphthalein pink B. acidic, which turns phenolphthalein colorless C. basic, which turns phenolphthalein pink D. basic, which turns phenolphthalein colorless
Answer:
C.
Explanation:
pH > 7, basic, so pH = 9 is basic.
When solution is basic, it will turn phenolphthalein pink.
A piece of lithium metal is added to a beaker that contains water and phenolphthalein. Using what you know about the properties of bases, choose the best explanation for what you observe.
Answer:
The phenolphthalein is turning pink because a base is forming.
A base has a molarity of 1.5M w.R.T the hydroxyl ion concentration. If 7.35 cm3 of this base is taken and diluted to 147 cm3, then what is the concentration of the hydroxyl ion.
Answer:
0.077M is the concentration of the hydroxyl ion
Explanation:
Dilution factor is the ratio between the aliquot that is taken of a solution and the total volume of the diluted solution.
For the problem, dilution factor is:
7.53cm³ / 147cm³ = 0.05122
To obtain molarity of a diluted solution you must multiply dilution factor and initial molarity of the solution, thus:
1.5 M × 0.05122 = 0.077M is the concentration of the hydroxyl ion