Chapter 12 Chemical Reactions and Equations

In a chemical reaction, the mass of the products

• is less than the mass of the reactants

• is greater than the mass of the reactants

• is equal to the mass of the reactants

• has no relationship to the mass of the reactants

Tags

NGSS.HS-PS1-7

How many moles of oxygen are required to react completely with 1.2 moles of hydrogen? YOU HAVE 5 MIN TO ANSWER THIS QUESTION. DON'T RUSH!

2H₂ + O₂ --> 2H₂O

• 1.2 mol

• 0.6 mol

• 2.4 mol

• 4.8 mol

Which of these expressions is the correct interpretation of the balanced equation?

2S + 3O₂ --> 2SO₃

• 2 g S + 3 atoms O2 --> 2 molecules SO3

• 2 g S + 3 g O2 --> 2 g SO3

• 2 mol S + 3 mol O2 --> 2 mol SO3

• none of the above

Tags

NGSS.HS-PS1-7

Which of the following words matches the definition: the reactant that is not completely used up in a reaction.

• actual yield

• limiting reagent

• excess reagent

• theoretical yield

What is actual yield?

• the amount of product formed when a reaction is carried out in a lab

• the reactant that determines the amount of product that can be formed in a reaction

• the calculated amount of product that might be formed during a reaction

• the calculation of quantities in chemical equations

A reaction that has been calculated to produce 60.0 g of CuCl2 actually produces 50.0 g of CuCl2. What is the percent yield?

YOU HAVE 5 MIN TO ANSWER THIS QUESTION. DON'T RUSH!

• 0.833%

• 96.1%

• 83.3%

• 120%

Tags

NGSS.HS-PS1-7

How many moles of NO2 are produced when 2.0 g of N2O4 are decomposed according to the following equation?

YOU HAVE 5 MIN TO ANSWER THIS QUESTION. DON'T RUSH!

N₂O₄ --> 2NO₂

• 4 mol NO2

• 2 mol NO2

• 0.04 mol NO2

• 184 mol NO2

Tags

NGSS.HS-PS1-7

How many grams of CO2 are produced when 68.0 g of CaCO3 is heated according to the following equation?

YOU HAVE 5 MIN TO ANSWER THIS QUESTION. DON'T RUSH!

CaCO3 --> CaO + CO2

• 0.679 g

• 29.9 g g

• 68.0 g

• 30.4 g

In any chemical reaction, the quantities that are conseved are

• the number of moles

• the number of molecules and the volumes

• mass and number of atoms

• mass and moles

Tags

NGSS.HS-PS1-7

Calculate the number of moles of water produced when 3.3 mol of Cu(NO3)2 are formed in the following reaction.

YOU HAVE 5 MIN TO ANSWER THIS QUESTION. DON'T RUSH!

3Cu + 8HNO3 --> 3Cu(NO3)2 + 2NO + 4H2O

• 4.4 mol

• 6.6 mol

• 4.9 mol

• 8.8 mol