From Chem AQ – Module 4 – ASSESSMENT SAMPLE SOLUTION by WL
To do: Choose one expectation of the course you will be teaching (SCH3UE, SBI3UE, SPH
3UE, SNC4M or SNC4E). Create one question for each achievement category that could be
given on a quiz or unit test. Provide the desired (level 4) response for each question and
indicate how you would evaluate a level 1 through 4 response with a small rubric. Use the
achievement chart rubric as a basis.
Solution:
From SCH3U
Expectation: E2.2 solve problems related to the concentration of solutions by performing
calculations involving moles, and express the results in various units (e.g., moles per litre, grams per
100 mL, parts per million or parts per billion, mass, volume per cent).
Strand: Solutions and Solubility
Question for ….
Knowledge & Understanding: What is a mole and molar mass in relation to an element?
Provide a definition, using an element as an example.
Thinking: Using the following equation, calculate how many grams of hydrogen gas are
required for 3.75g of nitrogen gas to react completely?
N2(g)
+
3 H2
→
2 NH3(g)
Communication: Use the GRASS or GRASP method (Given Required Analysis Solution
Sentence /Phrase) to demonstrate your thinking as you solve the problem.
Application: What mass of ammonia is formed when 3.75g of nitrogen gas react with
hydrogen gas according to the balanced equation?
Level 4 Exemplar Response:
Knowledge & Understanding:
An element’s molar mass is the mass of one mole of a pure substance.
A mole of an element represents 6.02 x 1023 particles of the element. When substances react
it is the particles within the elements which react. It is the unit used to count numbers of
atoms or molecules of substances.
Molar mass of nitrogen gas : 14.01 g /mol
1 mole of nitrogen gas contains 6.02 x 1023 atoms
Thinking: The amount of hydrogen needed depends on 2 things:
-the number of nitrogen molecules present in 3.75.
-the mole ratio of hydrogen gas to nitrogen gas in the balanced equation
Communication:
GIVEN:
-have 3.75g of Nitrogen gas; 1 mol of N2 ; Molecular weight (g/mol) of N2 = 28.02 g
REQUIRED:
-
how many grams of hydrogen gas are required for 3.75g of nitrogen gas to react
completely?
ANALYSIS:
Step 1: Calculate the number of moles of N2 in 3.75g:
X
1 mol of N2
= 3.75 g
28.02 g
X = 0.134 mol of N2
Step 2: The equation shows that 1 mol of N2 needs to react with 3 moles of H2. So we need
to calculate the number of hydrogen that will react with 0.134 moles of N2.
0.134 mol of N2
1 mol of N2
=
x mol of H2
3 mol of H2
X = 0.402 moles of H2
Step 3: Convert number of moles of hydrogen to molar mass.
Molecular weight of hydrogen = 2.016 g/mol
So, 0.402 moles of H2 x 2.016 g/mol = 0.81g of hydrogen
SENTENCE: 0.81 g of hydrogen is required to react with 3.75g of nitrogen.
Application:
Solution:
Step 1: Calculate the number of moles of ammonia that form when reacted with nitrogen.
From the balanced equation…1 mol of N2 : 2 mol of NH3
1 mol of N2 = 2 mol of NH3
0.134 of N2
y
0.286 mol of NH3 is formed.
The molar mass of NH3 is 17.0 g: 17.0 g x 0.268 = 4.55g.
Therefore, 4.55 g of NH3 is formed from 3.75 g of nitrogen.
How I would evaluate a Level 1 – 4 response?
Rubric
Criteria
Knowledge &
Understanding
Thinking
Level 1
The student…
-demonstrates
Does not
understanding of understand
relation of molar
mass, mole, &
balanced
equation
-does not use
terminology
-uses
correctly
terminology
correctly
-detailed
Does not follow
response
the
following the
GRASS/GRASP
GRASS/GRASP method or
method
similar method
-correctly uses
equations
Equations used
incorrectly
Level 2
Level 3
Level 4
Somewhat
understands
Understands
Has an
exceptional
understanding
Sometimes uses
terminology
correctly
uses terminology
correctly most of Always uses
the time
terminology
correctly
Uses the
GRASS/GRASP
method, but
inaccurately
Uses the
GRASS/GRASP
method
accurately most
of the time
Uses the
GRASS/GRASP
method
accurately always
correctly uses
equations most
of the time
Explanation &
wording is easy
to understand
Always correctly
uses equations
Solution is
organized in an
Communication Clear, logical
communication
Explanation &
wording is
difficult to
understand
Equations used
correctly
Sometimes
Explanation &
wording is
somewhat easy
to understand
Organizes
information and
Solution not
organized in an
Solution is
somewhat
Explanation &
wording is
exceptionally
easy to
understand
The organizer is
Application
solution in an
organizer
Is able to
complete second
part of question
(reverse process)
organizer
Cannot
complete second
part of question
organized in an
organizer
Struggles to
complete second
part of question
organizer
Can complete
second part of
question
very easy to
understand
Clearly
understands
second part of
question