C9: Chem Calculation (Concentration)

C9: Chem Calculation (Concentration)

Overview

Previously, we have done chemical calculations involving

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1) mass

2) volume of gases

3) Volume Ratio (Today!): learnt previously, more practices​

Overview

We will be doing chemical calculations involving

​

1) mass

2) volume of gases

3) Volume Ratio (Today!): learnt previously, more practices

4) Concentration (Now)​

5) Limiting reagent (next week)​

Toolkits for Chap 9 (Also revising for Chap 8)

QOTD

How to calculate quantities (chem calculation) involving a solution in a chemical reaction?

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(work out the answers on paper first, step by step)​

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Teacher's Demonstration

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​Step 1: Balanced chemical equation is completed!

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Which one is the "GIVEN" and "WANTED"?​

Multiple Choice

Refer to the teacher's demonstration, which one is the "GIVEN" and "WANTED" quantity of substances?

• Given: volume and concentration of sulfuric acid

  Wanted: Mass of zinc

• Wanted: volume and concentration of sulfuric acid

  Given: Mass of zinc

Teacher's Demonstration

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​Step 2: Find the No of Moles of GIVEN!

(Let's calculate and get ready to answer)​

Fill in the Blank

Calculate the number of mole of the "GIVEN" substance.

(Note: Someone will be picked to tell me something that might miss out)

Teacher's Demonstration

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Multiple Choice

Identify the mole ratio of the Given: Wanted.

• 1:1

• 1:2

• 0.005:1

Fill in the Blank

Calculate the number of mole of the "WANTED" substance.

(Note: Someone will be picked to explain how to get the number of moles)

Teacher's Demonstration

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Fill in the Blank

Calculate the mass of the "WANTED" substance.

(Note: Someone will be picked to explain how to calculate)

Teacher's Demonstration

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Classwork 1

Fill in the Blank

Calculate the number of mole of the "GIVEN" substance.

(Note: Someone will be picked to tell me something that might miss out)

Classwork 1

Multiple Choice

Identify the mole ratio of the Given: Wanted.

• 1:1

• 1:2

• 2:1

Fill in the Blank

Calculate the number of mole of the "WANTED" substance.

(Note: Someone will be picked to explain how to get the number of moles)

Classwork 1

Fill in the Blank

Calculate the mass of the "WANTED" substance.

(Note: Someone will be picked to explain how to calculate)

Classwork 1

Poll

Are you on the page for Classwork 2?

• Yes

• No

Fill in the Blank

Calculate the volume of carbon dioxide gas produced when excess calcium carbonate reacted with 35 cm³ of 0.25 mol/dm³ of hydrochloric acid.

(key in the value without the unit for this question)

CW2

Poll

Are you on the page for Classwork 3?

• Yes

• No

Fill in the Blank

25.0 cm³ of 0.105 mol/dm³ hydrochloric acid was neutralized by titrating it with 0.200 mol/dm³ potassium hydroxide. Calculate the volume of potassium hydroxide required? (round off to 3.s.f)

Poll

Are you on the page for Classwork 4?

• Yes

• No

Fill in the Blank

A solution of 25.0 cm³ sulfuric acid was titrated against a standard solution of 0.100 mol/dm³ potassium hydroxide. 20.8 cm³ of potassium hydroxide is required to reach the end-point of titration (completely reacted). Calculate the concentration of the acid in mol/dm³

Toolkits for Chap 9 (Also revising for Chap 8)