Chemical reactions

What holds together the atoms in a compound or molecule?

• Bonds

• Atom strings

• Mixtures

In a chemical reaction the bonds between the atoms break so the atoms can rearrange

• True

• False

A molecule or compound can change physically (eg freezing) by changing structure WITHOUT breaking bonds

• True

• False

In a chemical reaction, the things that react together (the things you start with) are called the...

• Products

• Reactants

• Starting mixtures

In a chemical reaction, the things that are produced by a reaction (the things you finish with) are called the....

• Reactants

• Finishing mixtures

• Products

Endothermic reactions...

• Take heat from the environment (feel cold)

• Give heat to the environment (feel hot)

Exothermic reactions...

• Take heat from the environment (feel cold)

• Give heat to the environment (feel hot)

Combustion reactions are usually endothermic

• True

• False

Hydrogen and oxygen → ___________

• Water - it's an explosive combustion reaction

• Don't react

• Carbon dioxide gas

Magnesium metal burns with ________ to give a bright white flame

• Oxygen

• Nitrogen

• Carbon dioxide