Chemistry NCFE 2018-19 #29-40

Front

What is a chemical reaction?

Back

A process that leads to the transformation of one set of chemical substances to another, typically involving the formation of new substances.

Front

What evidence indicates a chemical reaction has occurred?

Back

The formation of a new substance, which can be indicated by changes in color, temperature, gas production, or precipitate formation.

Front

What happens to potassium chloride (KCl) when it dissolves in water?

Back

Water molecules exert forces of attraction that break the potassium chloride apart into potassium ions and chloride ions.

Front

What does it mean if a solution is described as supersaturated?

Back

A solution that contains more solute than can be dissolved at a given temperature, often leading to crystallization if disturbed.

Front

What is the significance of litmus paper turning blue?

Back

It indicates that the substance being tested is likely a base.

Front

What effect does heating a reaction mixture have on the equilibrium?

Back

Heating a reaction can shift the equilibrium to favor the endothermic direction, often causing the reaction to shift to the left.

Front

What is the difference between a suspension and a colloid?

Back

A suspension contains larger particles that can settle out, while a colloid has smaller particles that remain dispersed and do not settle.

Front

What is the definition of a base in chemistry?

Back

A substance that can accept protons (H+) or donate electron pairs, often feeling slippery and turning red litmus paper blue.

Front

What is the role of water in dissolving ionic compounds?

Back

Water molecules surround and separate the ions in ionic compounds, allowing them to disperse in solution.

Front

What is an example of a physical change?

Back

Dissolving sugar in water, where the sugar can be recovered by evaporation.