Year 10 - Science
Mass in a chemical reaction
Calculations involving masses
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
This unit covers writing chemical formulae, balancing equations, and using the conservation of mass. It includes calculating moles, empirical formulae, relative formula masses, and theoretical yields. Emphasis is on stoichiometry, concentration, gas volumes, and using standard form.
Lesson Summary
You will learn to use conservation of mass and relative formula masses to predict the mass of unknown products or reactants.
Key Notes
- In a chemical reaction, the atoms in reactants are rearranged and are the same atoms that are in the products.
- The mass of products in a chemical reaction is equal to the mass of the reactants.
- The sum of the RFM of the reactants equals the sum of the RFM of the products, taking account of balancing coefficients.
Vocabulary To Learn
- balanced symbol equation: A balanced symbol equation represents a chemical reaction using symbols and coefficients to ensure that the number of atoms of each element is equal on both sides of the equation.
- conservation of mass: Conservation of mass means the total mass of the starting reactants equals the total mass of the products formed.
- relative formula mass: The relative formula mass (RFM or Mᵣ) of a substance is the sum of the relative atomic masses of all the atoms in its formula.
- coefficient: A coefficient is the number placed in front of a chemical formula to balance an equation; it multiplies all the atoms in the formula and shows the ratio of substances in a reaction.
Common Mistakes To Avoid
- Pupils struggle to recall the order of steps required to mathematically process the available information in order to answer the question.
3 Quick Questions (With Answers)
1. Explain the scientific idea in this lesson using two key points.
In a chemical reaction, the atoms in reactants are rearranged and are the same atoms that are in the products. The mass of products in a chemical reaction is equal to the mass of the reactants.
2. Define this scientific word and use it in context. 'balanced symbol equation'
A balanced symbol equation represents a chemical reaction using symbols and coefficients to ensure that the number of atoms of each element is equal on both sides of the equation. Include the word in a full scientific explanation, not as a single label.
3. Correct this common scientific misunderstanding.
Mistake: Pupils struggle to recall the order of steps required to mathematically process the available information in order to answer the question. Correction: Colour-coding the steps can help pupils remember how many steps are involved. Much practice and perseverance is needed to create and maintain the memory pathway of the mathematical processing.
More Lessons In This Unit
- Balancing equations Study Guide
- Conservation of mass Study Guide
- Converting between mass and volume using moles Study Guide
- Converting between mass and volume using moles (RAM 1 d.p.) Study Guide
- Deducing an empirical formula experimentally Study Guide
- Deducing an empirical formula experimentally: using moles Study Guide
- Determining an equation experimentally: magnesium oxide Study Guide
- Determining an equation experimentally: magnesium oxide (RAM 1 d.p.) Study Guide
- Determining an equation experimentally: sodium hydrogencarbonate Study Guide
- Determining an equation experimentally: sodium hydrogencarbonate (RAM 1 d.p.) Study Guide
- Determining an equation from given values Study Guide
- Determining an equation from given values (RAM 1 d.p.) Study Guide
- Empirical formula calculations Study Guide
- Empirical formula calculations: using moles Study Guide
- Gas volumes Study Guide
- Gas volumes (RAM 1 d.p.) Study Guide
- Limiting reactants Study Guide
- Limiting reactants (RAM 1 d.p.) Study Guide
- Mass in a chemical reaction (RAM 1 d.p.) Study Guide
- Mass in a chemical reaction: using moles Study Guide
- Mass in a chemical reaction: using moles (RAM 1 d.p.) Study Guide
- Moles and masses Study Guide
- Moles and masses (RAM 1 d.p.) Study Guide
- Representations of a mole Study Guide
- Representations of a mole (RAM 1 d.p.) Study Guide
- The mole Study Guide
- The mole (RAM 1 d.p.) Study Guide
- Three types of chemical reaction Study Guide
- Uncertainties in measurements: chemistry Study Guide
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