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Jamie Antoun

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Christian Lawson-Perfect

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10 years, 1 month ago

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Christian Lawson-Perfect 7 years, 2 months ago

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Christian Lawson-Perfect 10 years, 1 month ago

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Jamie Antoun 10 years, 10 months ago

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Question statement

Answer the following questions. Please enter your answers as decimals, not as fractions. Enter your answers to 2 decimal places.

If you would like to see how to do this question, click on 'Reveal answers' at the bottom of the page.

Give any introductory information the student needs.

			Name	Type	Generated Value

a	integer	5
c	integer	5
b	integer	9
d	integer	5

Automatically regenerate variables?

Name

Data type

Value

xxxxxxxxxx
 
random(1..9)

JME function reference

Description

Describe what this variable represents, and list any assumptions made about its value.

Can an exam override the value of this variable?

Generated value: `integer`

This variable doesn't seem to be used anywhere.

Parts

Part a) Gap-fill
1. Gap Number entry
  Add
Part b) Gap-fill
1. Gap Number entry
  Add

Gap-fill

Ask the student a question, and give any hints about how they should answer this part.

$\var{a}$ mole(s) of a substance are dissolved in $\var{b}$ litre(s) of a liquid to make a solution. What is the concentration of the solution in M (mol/L)?

Unnamed gap M

Advice

To answer these questions we use the formula

$\dfrac{\text{number of moles of substance}}{\text{volume of liquid (in litres)}} = \text{concentration (in mol/L)}$ .

a)

$\var{a}$ mole(s) of a substance are dissolved in $\var{b}$ litre(s) of a liquid to make a solution. What is the concentration of the solution in M (mol/L)?

Solution:

Putting our numbers into the formula, we find that the concentration is

$\begin{align}\dfrac{\var{a}}{\var{b}} & = \var{a / b} M \\ & = \var{precround((a / b), 2)} M \text{ to 2 d.p.} \end{align}$

b)

$\var{0.25 * c}$ mole(s) of a substance are dissolved in $\var{250 * d}$ ml of a liquid to make a solution. What is the concentration of the solution in M (mol/L)?

Solution:

The formula uses the volume of liquid in litres so we first have to convert $\var{250 * d}$ ml to a volume in litres. There are $1000$ ml in 1L so $\var{250 * d}$ ml is equal to

$\dfrac{\var{250 * d}}{1000} = \var{250 * d / 1000}L$ .

Putting our numbers into the formula, we find that the concentration is

$\begin{align}\dfrac{\var{0.25 * c}}{\var{250 * d / 1000}} & = \var{(0.25 * c) / (250 * d / 1000)} M \\ & = \var{precround(((0.25 * c) / (250 * d / 1000)), 2)} M \text{ to 2 d.p.} \end{align}$

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Number entry
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Metadata

Taxonomy: mathcentre

Taxonomy: Kind of activity

Taxonomy: Context

Contributors

Feedback

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Checkpoint description

Christian Lawson-Perfect 7 years, 2 months ago

Christian Lawson-Perfect 10 years, 1 month ago

Jamie Antoun 10 years, 10 months ago

Error in variable testing condition

Error

Warning

Generated value: `integer`

Parts

Gap-fill

a)

b)

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Solutions 1

Metadata

Taxonomy: mathcentre

Taxonomy: Kind of activity

Taxonomy: Context

Contributors

Feedback

History

Comment

Checkpoint description

Christian Lawson-Perfect 7 years, 2 months ago

Christian Lawson-Perfect 10 years, 1 month ago

Jamie Antoun 10 years, 10 months ago

Error in variable testing condition

Error

Warning

Generated value: integer

Parts

Gap-fill

a)

b)

Generated value: `integer`