Quantitative Chemistry Flashcards
What is the law of conservation of mass?
Where the total mass of the reactants have the exact same mass as the products.
How do u work out relative atomic mass of a compound?
Add up the relative atomic masses of each element.
Why might a substance lose or gain mass after a chemical reaction?
Normally, 1 of the reactants or products is a gas.
What are the three main examples of mass change in a chemical reaction?
1) Burning wood
2) Corrosion of metals
3) Zinc + hydrochloric acid
What is uncertainty in a chemical measurement?
For example, if a thermometer is displayed a reading of 35.4°C, the actual temperature could be anywhere between 35.35°C and 35.45°C.
How do you balance an equation?
All elements on both sides must have the same amount of atoms.
Example: H²+O² -> H²O = 2H² + O² -> 2H²O
What are moles?
Moles are a measurement of chemical reactions?
How big is 1 mole?
6.02x10²³ (Avogadro constant)
What is limiting reactant?
The reactant that is completely used up is called the limiting reactant because the reaction stops when it is used up.
What are the 4 factors that make sure the percentage yield of reactions stays below 100%?
- Incomplete reactions
- Side reactions
- Extraction
- Waste
What is the equation for percentage yield?
Percentage yield = real yield / theoretical yield x 100
What is theoretical yield?
The maximum mass of a product that could possibly be created from a reaction.
What is percentage yield?
Real yield divided by theoretical yield multiplied by 100
What is real yield?
The mass of a desired product obtained from a reaction.
What features of a reaction make it more likely to be incomplete?
- It is slow
- It is reversible
