Chemical Equations | Chemistry | Quiz

What is a chemical equation?

A way of calculating how many molecules are produced in a chemical reaction

A shorthand representation of what happens in a chemical reaction

A shorthand representation of the bonding in a molecule

A method of comparing diatomic molecules.
What are the substances on the left side of a chemical equation called?

Electrons

Groups

Products

Reactants
What does the number in front of a molecular formula mean in a chemical equation?

It shows that there is only one molecule present in a reaction

It shows the number of reactions that took place

It shows the number of that type of molecule involved in the reaction

All of the choices
Can the subscripts in a chemical reaction be changed?

Sometimes, depending on the energy released in the reaction

Yes, to balance the equation

Only for hydrogen, if there are water molecules on both sides of the reaction.

o, the subscripts define the molecules in the reaction
Lavoisier observed that the mass of reactants is the same as the mass of the products after a reaction. Which of the following can you NOT conclude based on Lavosiers observation:

The number of atoms in the reactants must be the same as the number of atoms in the products

The number of molecules of reactant must be the same as the number of molecules of products

No mass is lost or gained in the reaction

The Law of Conservation of Mass
The law of definite proportions implies that:

A chemical compound produced in a reaction will always have the same ratio of elements by mass, no matter what the source or amount of the reactants.

Each particular chemical reaction produces substances with definite sizes and physical proportions

The reactants in any chemical reaction will always create products in a one-to-one ratio

In a chemical reaction, the ratio of product molecules will always equal the ratio of reactant molecules
What does it mean when a chemical equation is balanced?

The equation represents equal weights of reactants and products

The total of the coefficients (including those that equal 1) is the same on both sides of the equation

There are the same number of molecules on either side of the equation

There are equal numbers of each type of atom on both sides of the equation
What coefficient should be in front of the oxygen? 4 Al + __ O₂ → 2 Al₂O₃

2

3

6

No number (the equivalent of the number 1)
What are the correct coefficients to balance this equation? 12 HClO₄ + ___ P₄O₁₀ → ____ H₃PO₄ + _____Cl₂O₇

1, 4, and 6

2, 4, and 4

1, 6, and 8

2, 6, and 4
If you begin this reaction with 1 mole of Ba₃N₂ and 6 moles of HF, how many moles of each product do you get? Ba₃N₂ + 6 HF → ___ BaF₂ + ___ NH₃

1 and 1

6 and 6

3 and 2

3 and 6