Chemical Equations, Acids and Bases

Chemical Equations, Reactions, Mixtures, Acids and Bases

Multiple Choice

In a chemical reaction, ________________________ are changed into _______________________.

• Reactants; Products

• Electrons; Molecules/Compounds

• Coefficients; Subscripts

• Original Elements; New Elements

Multiple Select

In the molecule below, which of the following choices is a subscript? (Select all that apply)

• 3

• 2

• 4

• SO

Multiple Choice

How many sulfur atoms are present in this molecule?

• 4

• 3

• 12

• 1

Multiple Choice

How are chemical bonds formed?

• Atoms duplicate themselves

• Electrons move from one atom to another

• The number of protons and electrons in an element is changed

• Through changes in an atom's nucleus

Multiple Choice

The first part of a balanced chemical equation is shown:  Cu + 2AgNO₃ → ________.  In order for this equation to be balanced, how many oxygen (O) atoms must be present in the products?

• 2
• 3
• 5
• 6

Multiple Choice

The law of conservation of matter states that:

• matter is neither created nor destroyed.
• the mass of the products is always greater than the mass of the reactants.
•  the mass of the products is always less than the mass of the reactants.
• matter is always converted into an equal amount of energy.

Multiple Choice

A teacher writes the equation representing the chemical reaction between hydrochloric acid and sodium on the board.HCl + Na → NaCl + H₂The teacher states that the equation has not been balanced. Which of these correctly shows the products of this reaction after the equation has been balanced?

• Na₂Cl + H₂
•  2NaCl + H₂
• NaCl + 2H₂
•  2NaCl + 2H₂

Multiple Choice

 The idea that matter is neither created nor destroyed in chemical reactions is known as the:

•  The idea that matter is neither created nor destroyed in chemical reactions is known as the:
• law of conservation of energy.
•  law of conservation of mass.
• second law of thermodynamics.

Multiple Choice

The first part of a balanced chemical equation is shown:  H₂SO₄ + 2NaOH → ________.  In order for this equation to be balanced, how many hydrogen (H) atoms must be present in the products?

• 2
• 3
• 4
• 5

Multiple Choice

Copper chloride and aluminum react to produce aluminum chloride and copper.  Which of the following is the correctly balanced chemical equation for this reaction?

• CuCl₂ + Al -> AlCl₃ + Cu
• 3CuCl₂ + Al -> AlCl₃ + 2Cu
• 3CuCl₂ + 2Al -> 2AlCl₃ + 3Cu
• CuCl₂ + 3Al -> AlCl₃ + 2Cu

Multiple Choice

Before a chemical reaction, the total mass of two reactants is measured to be 40 grams.  After the reaction, what should be the total mass of the products?

• 0 grams
• 20 grams
• 40 grams
• 80 grams

Multiple Choice

When two substances were combined, bubbles were produced and the temperature dropped. This most likely means that:

• a chemical reaction took place

• the two substances had low boiling points

• one substance dissolved in the other

• the two substances are non-reactive

Multiple Choice

The higher the concentration of negative (hydroxide) ions in the solution, the stronger the base is.

• True

• False

Multiple Choice

An acid is a solution that contains __________ ions dissolved in water.

• positive

• negative

Multiple Choice

The pH value of an acid represents its __________ of positive ions in the solution

• amount

• concentration

• color

• charge

Multiple Choice

The strongest bases have pH values close to

• 0

• 14

• 7

• 5

Multiple Choice

Which of the following is a property of a base?

• bitter taste

• reacts with metals

• salty

• sour taste

Multiple Choice

Milk is a very weak acid. What might its pH value be?

• 6.5

• 7.8

• 4.2

• 12.2

Multiple Choice

Which of these pH values represent an acid?

• 4

• 8

• 10

• 12