Download Learning objectives - The John Warner School

Course
Subject
Topic
Pages
Additional
science
Chemistry
C2 3.4 Equations and
calculations
Pages 114–115
Learning objectives
Learning outcomes
Specification link-up
Kerboodle
Students should learn:
 that balanced symbol equations show
the relative numbers of molecules of
reactants and products in a reaction
[HT only]
 that balanced symbol equations can be
used to calculate the masses of
reactants and products. [HT only]
Most students should be able to:
 interpret how many moles of
reactants/products are shown in a
balanced symbol equation [HT only]
 balance symbol equations [HT only]
 use a balanced symbol equation to
calculate the mass of reactants or
products. [HT only]
The masses of reactants and
products can be calculated from
balanced symbol equations.
[C2.3.3 c)] [HT only]
Maths skills:
Equations and
calculations
Extension:
How much?
Lesson structure
Support, Extend and Practical notes
Starters
Multiple-choice – Give each student three coloured flashcards, e.g. blue, green and red.
Then create a few multiple-choice questions, one per slide on PowerPoint, with three
answers, each one written in a different colour to match the flash cards. This could also be
achieved using Word or whiteboard software. Then show each question in turn and the
students hold up the card that represents the answer they think is correct. (5 minutes)
Chemical equations – Ask the students to complete the following chemical equations:
1 Mg + [O2] → 2MgO
2 CH4 + O2 → [CO2] + 2H2O
3 Zn + CuSO4 → [Cu] + [ZnSO4]
4 [NaOH] + HCl → NaCl + H2O
Then students could turn these into balanced symbol equations. Support students by giving
them the missing words. To extend this activity, you could ask the students to say what type
of reaction each of the above represents [1 oxidation; 2 combustion/oxidation; 3
displacement; 4 neutralisation]. (10 minutes)
Main
Students may have been introduced to balancing symbol equations in Key Stage 3 and will
have covered it during their studies of C1. You may wish to return to the familiar equation for
the oxidation of hydrogen, which is often used to demonstrate balancing equations. Advance
students by explaining that the numbers that are used to balance the equation can be
thought of as a ratio. Therefore two molecules of hydrogen will react with one molecule of
oxygen to make two molecules of water. However, as this is a ratio, we can also say that two
moles of hydrogen will react with one mole of oxygen to make two moles of water. You may
then wish to work through the calculation example given in the Student Book for the reaction
between hydrogen and chlorine.
Students need to be able to work out the masses of different substances in balanced symbol
equations. Create a card loop by drawing a rectangle 10 cm by 15 cm. Draw a dotted line to
make a square 10 cm by 10 cm. In the square, write out questions that involve balancing
equations and calculating reacting masses. Then, in the 5 cm by 10 cm rectangle, write an
answer (not one that matches the question on the card). Ensure that the questions match
answers on other cards so that a loop is made. Give the question loop set to small groups of
students and allow them to complete the card sort. Then encourage the students to pick two
of the questions and answers to copy into their book, but show their working out stage by
stage (as demonstrated in the Student Book).
Split the class into pairs, and on separate pieces of paper write enough calculation questions
for one per group. Give out the questions and allow the students to start to answer for 3
minutes (timed using a stopwatch). Then ask the students to hand the paper to another
group. Give the next group 3 minutes to correct the previous work and then continue with the
answer. Repeat this a number of times until there has been enough time for the answers to
be completed. Then return the paper back to the ‘owners’ where they should copy up the
question and the full answer.
Plenaries
Reflection – Ask students to think about the objectives for today’s lesson. Ask them to consider if
they have been met, and discuss this in small groups. Ask a few groups to feed back to the rest of
the class, explaining how they know that they have met the objectives. (5 minutes)
AfL (Assessment for Learning) – Give students some calculations but, instead of tackling
the questions, encourage them to create the mark scheme. Ask the students to work in small
groups discussing the questions and devising the marking points, and include alternative
answers that could still be given credit, and those that definitely should not be awarded
marks. This activity can be differentiated by using questions from the tier of entry students
are being entered for. (10 minutes)
Support
Some students will find the calculations difficult. Give
them half-finished calculations, where they need to
add numbers into the working out to generate the
answers. Peer mentoring could also be used, where
the students are split into pairs, with Higher Tier
students supporting Foundation Tier students.
Extend
Give students more complex symbol equations to
complete calculations. Include data that would
encourage students to truncate answers.
Text © Ruth Miller, Geoff Carr, Darren Forbes, Sam Holyman 2011