Stoichiometry Part 2 gen chem

Multiple Choice

Why is stoichiometry important in understanding chemical reactions?

• It helps predict the amount of products formed.

• It determines the color of chemicals.

• It explains the physical state of substances.

• It identifies the laboratory equipment needed.

Multiple Choice

Which statement best explains the law of conservation of mass in a chemical reaction, as shown in the diagrams and text?

• Atoms are destroyed during a chemical reaction.

• Atoms are created during a chemical reaction.

• The number and types of atoms remain the same on both sides of the reaction.

• The mass of products is always less than the mass of reactants.

What we start with, On the LEFT of the arrow!

What we end with, On the RIGHT of the arrow!

Multiple Select

Which of the following are true about chemical equations and the law of conservation of mass?

• Chemical equations must be balanced.

• Mass cannot be created or destroyed in a chemical reaction.

• Reactants and products must have the same number of atoms for each element.

• Subscripts can be changed to balance equations.

Open Ended

Explain why chemical equations must be balanced and how coefficients and subscripts help achieve this.

The atoms on both sides are not equal

Open Ended

How does the unbalanced equation H2 + O2 → H2O violate the law of conservation of mass?

Multiple Choice

What do we use to balance chemical equations?

• Coefficients

• Subscripts

• Reactants

• Products

Open Ended

Why don't we use grams as the units for measuring the mass of atoms?

An element by itself

An element bonded to the same element. example Br2

Multiple Select

Which of the following are monoatomic elements?

• Neon

• Oxygen

• Nitrogen

• Helium

Multiple Choice

What is the difference between gram formula mass and formula mass?

• Gram formula mass is measured in grams, formula mass is measured in AMU.

• Gram formula mass is for atoms only, formula mass is for molecules only.

• Gram formula mass is for compounds only, formula mass is for elements only.

• Gram formula mass is measured in AMU, formula mass is measured in grams.

Open Ended

What is the formula mass of K2CO3?

Open Ended

What is the gram formula mass of CO2?

The percentage of the mass of a molecule that part of it takes up

Open Ended

What is percent composition?

Multiple Select

Select all steps required to calculate the percent composition by mass for CaCl2.

• Calculate the GFM for CaCl2.

• Find the mass of each element in CaCl2.

• Balance the equation for CaCl2.

• Plug values into the percent composition formula.

Multiple Choice

Which of the following steps is NOT part of calculating percent composition by mass for a compound?

• Calculate the gram formula mass (GFM) for the compound.

• Check the reference table for the formula.

• Plug in values to the formula and solve.

• Balance the chemical equation.

Open Ended

What is the percentage by mass of carbon in CO2?

Open Ended

What is the percentage by mass of oxygen in Fe2O3?

Open Ended

Reflecting on today's lesson about stoichiometry and reaction classification, what is one concept you found most interesting or would like to explore further?

Multiple Choice

Which type of chemical reaction is represented by the equation: 2NaClO3 (s) → 2NaCl (s) + 3O2 (g) + Heat?

• Decomposition

• Synthesis

• Single displacement

• Combustion

Open Ended

Describe the difference between a reactant and a product in a chemical reaction.