Science chapter 8 test

What is burning?

A chemical reaction in which a substance combines with oxygen.

Name some examples of fuels for burning

Charcoal, wood, coal, natural gas, and oil

What is another term for burning?

Combustion

What is an exothermic reaction?

A chemical reaction in which thermal energy is given out and increases the temperature of the surroundings

What are the 3 things needed for burning to take place?

Oxygen, heat, and fuel

Construct the chemical reaction that is used to form water.

Hydrogen + oxygen (arrow) water

Construct the exothermic reaction in which magnesium is burned

Magnesium + oxygen (arrow) magnesium oxide

What is an oxidation reaction?

A reaction in which a new substance combines with oxygen

Construct the equation for the exothermic reaction between potassium and water

Potassium + water (arrow) potassium hydroxide + hydrogen

Construct the equation for the exothermic reaction between magnesium and dilute hydrochloric acid

magnesium + hydrochloric acid (arrow) magnesium chloride + hydrogen

What is an endothermic reaction?

A chemical reaction in which thermal energy is absorbed from their surroundings and changed into chemical energy which is stored in the chemical bonds.

Constroct the endothermic word equation for the reaction between sodium hydrogencarbonate and citric acid

sodium hydrogencarbonate + citric acid (arrow) sodium citrate + water + carbon dioxide

Name an endothermic process

Ice melting

Name the chemical word equation for rust

iron + oxygen (arrow) iron oxide

What are the causes of iron rusting?

When the iron is exposed to water and oxygen

What are non reactive substances called?

inert

What is the word equation format for when any metal reacts with oxygen?

metal + oxygen (arrow) metal oxide

What is the word equation format for when any metal reacts with water?

metal + water (arrow) metal hydroxide + hydrogen

What is the word equation for when a metal reacts with acid?

metal + acid (arrow) salt + hydrogen

What is the test for hydrogen called?

The squeaky pop test. You get a burning splint and bring it close to the gas, if hydrogen is present then it burns witha squeaky pop.

What is the test for carbon dioxide called?

The limewater test. You get some limewater and pass it thorugh the gas, if the gas turns cloudy than carbon dioxide is present.

Name an exothermic reaction

Potassium + water (arrow) potassium hydroxide + hydrogen

Name an endothermic reaction

sodium hydrogencarbonate + citric acid (arrow) sodium citrate + water + carbon dioxide

what is an independent variable?

The variable that you change

What is the dependent variable?

The variable that you measure

What is the controlled variable?

The variable that stays the same