Balanced equations

Question 1

What is a balanced equation?

Answer 1

A chemical equation is said to be balanced when there are the same number of the same type of every atom on both sides of the equation.

Question 2

What is the formula for calculating mass?

Answer 2

number of moles=

mass/formula mass

Question 3

What are the steps to answering a “calculate the mass” question?

Answer 3

1. Balance the equation
2. Use the balanced equation to work out how many moles of product this equates to using mole ratios

3.Calculate the mass of product produced using the moles calculated in step 3 and the gram formula mass of the product.

Question 4

What is the formula to calculate percentage mass?

Answer 4

Percentage mass=

mass of elements / X 100%
GFM

Question 5

What are the steps to complete a ‘Calculate percentage mass’ question?

Answer 5

1. Write the formula for the compound
2. calculate the GFM
3. Finally, divide the gram formula mass for iron by the total gram formula mass of iron (III) oxide and convert to a percentage