Module: Conservation of Matter
DCI: PS1.B (C) The fact that atoms are conserved, together with
knowledge of the chemical properties of the elements involved, can be used to
describe and predict chemical reactions.
PE: HS-PS1-2 Construct and
revise an explanation for the outcome of a simple chemical reaction based on
the outermost electron states of atoms, trends in the periodic table, and
knowledge of the patterns of chemical properties.
[Clarification
Statement: Examples of chemical reactions could include the reaction of sodium
and chlorine, of carbon and oxygen, or of carbon and hydrogen.] [Assessment
Boundary: Assessment is limited to chemical reactions involving main group
elements and combustion reactions.]
PE: HS-PS1-7 Use mathematical representations to support the claim
that atoms, and therefore mass, are conserved during a chemical reaction.
[Clarification Statement: Emphasis is on using
mathematical ideas to communicate the proportional relationships between masses
of atoms in the reactants and the products, and the translation of these
relationships to the macroscopic scale using the mole as the conversion from
the atomic to the macroscopic scale. Emphasis is on assessing students’ use of
mathematical thinking and not on memorization and rote application of
problem-solving techniques.] [Assessment Boundary: Assessment does not include
complex chemical reactions.]
The ideas in this standard are:
- we can use the knowledge that mass is conserved during a chemical reaction to describe and predict them
- we also need to know the chemical properties of the elements involved to describe and predict what will happen during the chemical reaction
In order to address the PE - students will need to evaluate a chemical reaction and then explain what happened based on electron arrangement, periodic trends, and chemical properties of elements. We will have to supply a chemical equation in order to do this. (Why did sodium bond with chlorine?, etc)
Additionally, the second PE is just balancing equations. Ideas related to the mole conversions are acceptable here. The emphasis though, clearly, is on using mathematical thinking and not necessarily carrying out a complicated problem-solving technique.
Possible Question Starters:
"A chemical equation is provided.
Al + H2SO4 → H2 + Al2(SO4)3
Which of the following best explains why, when the equation is balanced, there are three (SO4) molecules attached to the Aluminum atoms?"
"How many moles of H2O are produced if 15.9 grams of C2H6 react with an excess of O2?
2 C2H6 + 7 O2 → 4 CO2 + 6 H2O"
No comments:
Post a Comment