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Amounts of Substances in Equations (AQA GCSE Chemistry Combined Science): Quizzes

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Amounts of Substances in Equations

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What do the numbers in front of formulas in a balanced equation represent?

The ratio of moles of each substance

In $Mg + 2HCl → MgCl_2 + H_2$ , how many moles of $HCl$ react with 1 mole of $Mg$ ?

2 moles

In $Mg + 2HCl → MgCl_2 + H_2$ , how many moles of $H_2$ are produced from 1 mole of $Mg$ ?

1 mole

What is the formula to calculate moles from mass?

Moles = mass ÷ $M_r$

If you have 6g of $Mg$ and the $M_r$ of $Mg$ is 24, how many moles of $Mg$ do you have?

0.25 moles

What does $M_r$ represent when calculating moles?

Relative molecular mass

For elements, what should you use instead of $M_r$ to calculate moles?

$A_r$

In $Mg + 2HCl → MgCl_2 + H_2$ , how many moles of $MgCl_2$ form from 1 mole of $Mg$ ?

1 mole

Once you know the moles of a substance, what helps you find amounts of other substances?

Mole ratios from the balanced equation

Explore AQA GCSE Chemistry Combined Science Revision Notes by Topics

Measurement, Mass & Equations

Calculating Mass of Substances

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Measurement, Mass & Equations

Calculating Mass of Substances

Explore AQA GCSE Chemistry Combined Science Flashcards by Topics

Measurement, Mass & Equations

Calculating Mass of Substances

Explore AQA GCSE Chemistry Combined Science Exam Questions by Topics

Measurement, Mass & Equations

Calculating Mass of Substances

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