11th Chemistry- Stoichiometry

Question 0

The mole ratio of two components in a chemical reaction is determined from the 
A. Mass of each component
B. Coefficients of each component
C. Volume of each component
D. Number of atoms of each component

Answer 0

B. Coefficients of each component

Question 1

Match the following
1. Molar mass. A. Calculations of quantities/amounts
In chemical reactions
2. Stoichiometry. B. Mass in grams of one mole of a substance
3. Coefficients. C. Process forming a new substance
4. Chemical reaction. D. Numbers used to balance equation

Answer 1

Molar mass - Mass in grams of one mole of a substance
Stoichiometry- Calculations of quantities/amounts in chemical reactions
Chemical reaction - Process forming a new substance
Coefficients - Numbers used to balance equation

Question 2

When following the “mass A –> mole A –> mole B –> mass B”
Stoichiometry calculation steps, the “mass A” is converted into “mole A” by using the
A. Coefficients
B. Mole ratio of substance A to substance B
C. Molar mass of substance A
D. 6.02 x 10^23 number conversion

Answer 2

C. Molar mass of substance A

Question 3

Knowing the mole ratio of a reactant and product in a balanced chemical equation would allow you to determine
A. The energy released in the reaction
B. The speed of the reaction
C. The moles of unknown(what you’re solving for) from moles given in the problem
D. None of the above

Answer 3

C. The moles of unknown(what you’re solving for) from moles given in the problem

Question 4

2 ZnS + 3 O2 --> 2 ZnO + 2 SO2
If you have 7.25 moles of O2, how many moles of SO2 are produced?
A. 3.00 moles
B. 4.83 moles
C. 6.75 moles
D. 7.25 moles

Answer 4

B. 4.83 moles

7.25 moles O2 x 2 SO2/3 O2 = 4.83 moles SO2

Question 4

2 ZnS + 3 O2 --> 2 ZnO + 2 SO2
If you have 3.00 moles of ZnS, how many moles of O2 are needed to react with it?
A. 2.00 moles
B. 2.67 moles
C.  3.00 moles
D. 4.50 moles

Answer 4

D. 4.50 moles

3 moles x. 3/2 = 4.5 mole
3 O2 per 2 ZnS mole ratio

Question 6

The molar mass of a compound in a chemical reaction is determined by:
A. Coefficients of each compound
B. Volume of each compound
C. Adding up the masses of the elements in the compound
D. Number of atoms in each compound

Answer 6

C. Adding up the masses of the elements

Question 7

How many grams of BaCl2, barium chloride, are needed to completely react with 7.5g AgNO3, silver nitrate? 
2 AgNO3 + BaCl2--> 2 AgCl + Ba(NO3)2
A. 9.1g BaCl2
B. 2.5g BaCl2
C. 3.2g BaCl2
D. 4.6g BaCl2

Answer 7

????

Question 8

How many particles are there in a mole?
A. 6.23 x 10^5
B. 6.02 x 10^23
C. Depends on mole ratios
D. Depends on molecular mass ratio

Answer 8

B. 6.02 x 10^23

Question 9

Why must you have balanced equations in stoichiometry equations?
A. There must always be ionic balance
B. Conservation of mass
C. Conservation of energy
D. 2nd amendment to the Constitution guarantees it

Answer 9

B. Conservation of mass.

Moles of reactants must balance moles of products

Question 10

Methane (CH4) burns in oxygen (O2) to form carbon dioxide (CO2) and water (H20)

Write the balance equation for this.

Answer 10

CH4 + 2 O2 –> CO2 + H2O

Question 11

CH4 + 2 O2 –> CO2 + H2O

What number of moles of oxygen gas is required to react with 7.4 mol methane (CH4)?

Answer 11

7.4mol CH4 x 2 O2/CH4 = 3.7 mol O2

Question 12

CH4 + 2 O2 –> CO2 + H2O
How many moles of carbon dioxide gas (CO2) will be produced by reacting with 2.6 mole of oxygen with excess methane (CH4)?

Answer 12

2.6 mole O2 x 1 mole CO2/2 mole O2= 1.3 mole CO2