Chemical Reactions and Balancing Aks

In a chemical equation, is it true that -

• the reactant side and product side can have different numbers of atoms for each element
• there can be different elements on the reactant side and the product side
• an element or compound must be accompanied by a phase change
• the coefficients indicate the number of molecules of each reactant used and the number of molecules of each product made

Tags

NGSS.MS-PS1-5

Which of the following models best demonstrates a balanced chemical equation?

• F
• G
• H
• J

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-2

NGSS.MS-PS1-5

The formula below represents the most common carbohydrate known as glucose. Which information can be determined from the chemical formula?
C₆H₁₂O₆

• The structural arrangement of the atoms in a glucose molecule
• The color of a glucose molecule
• The size of a glucose molecule
• The number of atoms of each element in a glucose molecule

Tags

NGSS.MS-PS1-1

For an investigation a student poured a blue solution of CuSO₄ into a beaker. The student placed a shiny, silver-colored strip of zinc metal in the solution and observed the changes.
The student inferred that a chemical reaction occurred. What evidence supports this inference?

• A dark solid formed on the zinc metal.
• 
  The zinc metal remained silver-colored and shiny
• The CuSO₄ solution turned blue when the zinc metal was added.
• None of these

Tags

NGSS.MS-PS1-2

Which of the following equations demonstrates an actual chemical reaction that forms a new substance?

• A
• B
• C
• D

Tags

NGSS.MS-PS1-2

The chemical formula for glucose, a simple sugar, is C₆H₁₂O₆. The formula for ethanol is C₂H₆O. What accounts for the differences in these compounds?

• The elements that make up glucose are different than the elements that make up ethanol
• The ratio of the elements is different in ethanol than in glucose
• The chemical properties of the elements are different in glucose and ethanol
• Glucose has more elements than the ethanol

Tags

NGSS.MS-PS1-1

Which of these formulas contain equal numbers of nitrogen atoms?

• Formulas I and III
• Formulas I and IV
• Formulas II and III
• Formulas I, II, and V

Tags

NGSS.MS-PS1-1

The reactants are on the left side of the chemical equation.

• True
• False

Two clear colorless solutions were combined.
The student observed that the temperature changed from 25 •C to 23 •C when the solutions were combined and that a white substance rapidly formed and settled to the bottom of the container. What most likely happened to produce these results?

• One of the original compounds came out of solution
• The solutions reacted chemically
• Some of the water froze into ice crystals
• Rapid evaporation of water occurred, leaving a solid

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

The equation below represents a chemical reaction that occurs in living cells. How many atoms are represented in the reactants of this equation?

• 6
  6
• 12
  12
• 24
  24
• 36
  36

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-2

NGSS.MS-PS1-5