Physical Science Semester 2 Practice Quiz

Each substance to the right of the arrow in a chemical equation is a(n) _______.

• Catalyst

• Product

• Reactant

• Inhibitor

Answer explanation

Each substance to the right of the arrow in a chemical equation is referred to as a 'Product'.

The numbers that go before symbols and formulas in a chemical equation are _______.

• Superscripts

• Subscripts

• Catalysts

• Coefficients

Answer explanation

The numbers that go before symbols and formulas in a chemical equation are called coefficients, which represent the ratio of moles of each substance involved in the reaction.

Substances that speed up chemical reactions are called _______.

• Inhibitors

• Products

• Reactants

• Catalysts

Answer explanation

Substances that speed up chemical reactions are called Catalysts.

A(n) _______ chemical equation has the same number of atoms of each element on each side of the equation.

• unbalanced

• balanced

• simple

• complex

Answer explanation

A balanced chemical equation has the same number of atoms of each element on each side of the equation, making it the correct choice.

If something is burned, a _______ reaction has occurred.

• double displacement

• single displacement

• combustion

• synthesis

Answer explanation

If something is burned, a combustion reaction has occurred.

Why does an increase in temperature result in an increase in reaction rate?

• It raises the activation energy

• It causes the molecules to increase in size

• It decreases the concentration of reactants

• It causes an increase in the number of particle collisions

Answer explanation

An increase in temperature causes an increase in the number of particle collisions, leading to a higher reaction rate.

If energy must be added to a chemical reaction for the reaction to take place, the reaction is ___.

• exergonic

• endergonic

• exothermic

• endothermic

Answer explanation

If energy must be added to a chemical reaction for the reaction to take place, the reaction is endergonic.

In a chemical equation, the symbol that means dissolved in water is ___.

• (s)

• (l)

• (g)

• (aq)

Answer explanation

In a chemical equation, the symbol that means dissolved in water is (aq). This notation stands for 'aqueous solution'.

What type of reaction is the following chemical reaction? CH3CH2OH + 3O2 → 2CO2 + 3H2O

• double-displacement

• single-displacement

• combustion

• synthesis

Answer explanation

The given chemical reaction CH3CH2OH + 3O2 → 2CO2 + 3H2O is a combustion reaction, where a substance reacts with oxygen to produce heat, light, and new products.

Which chemical reaction represents a double displacement reaction?

• 2Na + Cl2 → 2NaCl

• 2KClO3 → 2KCl + 3O2

• Zn + 2HCl → ZnCl2 + H2

• NaOH + HCl → NaCl + H2O

Answer explanation

The correct choice for a double displacement reaction is NaOH + HCl → NaCl + H2O.