Chapter Flashcards
What do the coefficients in a chemical reaction specify?
The relative amounts in moles of each of the substances involved in the reaction
Coefficients indicate the ratio of reactants and products in a balanced chemical equation.
In the balanced equation 2 C8H18 + 25 O2 → 16 CO2 + 18 H2O, how many molecules of CO2 are produced from 2 molecules of C8H18?
16 molecules of CO2
This reflects the stoichiometric ratio from the balanced equation.
What is the first step in balancing a chemical equation?
Write a skeletal equation by writing chemical formulas for each of the reactants and products
A skeletal equation serves as the starting point for balancing.
When balancing chemical equations, which ions should be balanced second?
Nonmetal ions (anions)
If a polyatomic anion exists on both sides, balance it as a unit.
Fill in the blank: The stoichiometric ratio acts as a ______ between the amount in moles of a reactant to moles of a product.
conversion factor
What is the stoichiometric ratio of C8H18 to CO2 in the combustion reaction?
2 moles C8H18 : 16 moles CO2
This ratio is derived from the balanced equation.
How many moles of CO2 are produced when 22.0 moles of C8H18 are combusted?
176 moles of CO2
Calculation based on the stoichiometric ratio.
What is the mass of CO2 produced when 3.6 × 10^15 grams of C8H18 is burned?
1.1 × 10^16 grams of CO2
This is determined through mole-to-mass conversion using stoichiometric ratios.
What should be done if the balanced equation contains coefficient fractions?
Clear these by multiplying the entire equation by the denominator of the fraction
This ensures whole number coefficients for clarity.
When balancing a chemical equation, which type of atoms should be balanced last?
Free elements
Always adjust the coefficient on the free element to balance.
True or False: In a balanced equation, the total number of each type of atom on both sides must be the same.
True
List the steps for balancing chemical equations.
- Write a skeletal equation
- Balance metal ions first
- Balance nonmetal ions second
- Balance free elements last
- Clear coefficient fractions if necessary
- Check the balance
Following these steps ensures a systematic approach to balancing equations.
What is the balanced equation for the combustion of butane (C4H10) with oxygen?
C4H10 + O2 → CO2 + H2O
This skeletal equation needs to be balanced through the steps outlined.
What is the balanced equation for the combustion of butane (C4H10)?
C4H10(g) + 5 O2(g) → 4 CO2(g) + 5 H2O(g)
This equation shows butane reacting with oxygen to produce carbon dioxide and water.
What defines a chemical change?
Changes that alter the composition of matter
During a chemical change, atoms rearrange to form new substances.
Give an example of a chemical change.
Rusting of iron
Rust occurs when iron reacts with oxygen, forming iron(III) oxide (Fe2O3).
What is a physical change?
Changes that alter only the state or appearance without changing composition
Example: Water boiling to become steam.
What is the average rise in atmospheric temperature since 1860?
0.8 °C (1.4 °F)
This temperature change coincides with a 37% rise in atmospheric CO2 levels.
What are greenhouse gases?
Gases that allow sunlight in, warm the Earth’s surface, and prevent heat from escaping
They play a crucial role in the greenhouse effect.
What is stoichiometry?
The study of the numerical relationship between chemical quantities in a chemical reaction
It involves balancing chemical equations and calculating reactants and products.
What is a limiting reactant?
The reactant that is completely consumed in a reaction
It determines the maximum amount of product that can be formed.
What is the theoretical yield?
The maximum amount of product that can be formed from the limiting reactant
It is calculated based on stoichiometry.
What is a physical change?
Changes that alter only the state or appearance, but not the composition
The identity of the substance remains the same.
Fill in the blank: A _____ change results in a new substance being formed.
chemical
