Chemical reactions

What can represent chemical reactions

Word equations cam represent a chemical reactions

what is an example of a word equation

methane + oxygen → carbon dioxide + water

What is on the left side of the arrow

The reactants are on the left side of the arrow

what is on the right side of the arrow

The products are on the right side of the arrow

Why do we use an arrow instead of an equals sign

We use an arrow instead of an equals sign as it represents that the reactants are changing into a new substance

What stays the same in a reaction

In a reaction, the amount of each atom stays the same

what changes in a reaction

In a reaction the the atoms a rearranged to form a new product

What will happen to the mass in a reaction

In a reaction the mass will be conserved this means that the total mass of the reactants will be equal to the total mass of the products

Why can it appear some mass has been lost

If it appears some mass has been lost this is because a gas has been produced and escaped, accounting for the lost mass

What is a chemical reaction

A chemical reaction is a change in which atoms are rearranged to make new substances.

What is different between the reactants and the products

The atoms are joined together one way before the reaction and a different way after the reaction

What takes part in chemical reactions

Elements and compounds take part in chemical reactions

Are Chemical reactions reversible

Chemical reactions are not easily reversible, at the end of a chemical reaction it is difficult to get back what you started with

Can products transfer energy to the surroundings

As well as making new substances, chemical reactions also transfer energy to or from the surroundings

How do you know if its a chemical reaction

Huge flames

tiny sparks

feel the substance getting hotter

or colder

sweet smell

foul stink

loud bang

gentle fizzing

Are all changes chemical reactions

Not all changes involve chemical reactions.

What is an example of a physical change

If you warm chocolate it melts. But you still have chocolate. Changes of state and dissolving are reversible. This means you can get back what you started with. These are called physical changes