Lesson Quiz: Lesson 8.1

Find and correct the error(s) in the equation so it is correctly balanced: 2HI (aq) + 2Pb(NO3)2 (aq) → PbI2 (s) + 2HNO3 (aq). Which of the following is the correctly balanced equation?

• 2HI (aq) + 2Pb(NO3)2 (aq) → PbI2 (s) + 2HNO3 (aq)

• 4HI (aq) + 2Pb(NO3)2 (aq) → 2PbI2 (s) + 4HNO3 (aq)

• 2HI (aq) + Pb(NO3)2 (aq) → PbI2 (s) + 2HNO3 (aq)

• 4HI (aq) + Pb(NO3)2 (aq) → PbI2 (s) + 4HNO3 (aq)

What do word equations use to indicate reactants and products of chemical reactions?

• symbols

• descriptions

• names

• coefficients

In this equation, which are the reactant(s)? Mg (s) + O2 (g) → MgO (s)

• B only

• C only

• A only

• A and B

In a chemical equation, (aq) after one of the substances means that it is which of these?

• released as gas

• a solid formed from two ionic substances

• dissolved in water

• produced from nothing

How many total atoms are in three formula units of Na2SO4?

• 7

• 10

• 24

• 21

What are the correct coefficients when this chemical equation is balanced? P₄ + O₂ → P₂O₅

• 1, 5, 2

• 2, 5, 4

• 1, 1, 1

• 4, 2, 7

The balanced chemical equation 2Zn (s) + 4HCl (aq) → 2ZnCl₂ (aq) + 2H₂ (g) is presented. What is wrong with it?

• The stoichiometric coefficients for the reactants and products are incorrect.

• The physical states of the substances are misrepresented.

• There is an extra reactant in the equation.

• Nothing is wrong with the balanced chemical equation.

Write the correct balanced equation for the reaction: solid mercury(II) oxide yields liquid mercury plus oxygen gas.

• HgO(s) → Hg(l) + O2(g)

• 2 HgO(s) → 2 Hg(l) + O2(g)

• 2 HgO(s) → Hg(l) + O2(g)

• HgO(s) → Hg(l) + 1/2 O2(g)

What is the name for a chemical equation that shows the chemical formulas of the substances involved but no coefficients?

• word equation

• skeleton equation

• balanced equation

• net ionic equation