Lecture 2- Chemical Calculations Flashcards
What are the reactants in a chemical reaction?
Substances that REACT together.
What are the products in a chemical reaction?
Substances PRODUCED in the reaction.
What does a word equation provide?
Names of the substances involved in a reaction.
What is a balanced equation?
It gives the symbols and formulas of the substances involved in a reaction.
What is the formula for balancing equations?
Adjust the number of units of some substances until equal numbers of each type of atom are on both sides of the arrow.
What is RAM?
Average mass of a large number of atoms of an element.
What is RMM?
Average mass of a molecule calculated by adding the RAMs of all atoms in the formula.
What is the definition of a mole (mol)?
Amount of a substance that contains as many particles as the number of atoms in exactly 12g of carbon-12.
What is Avogadro’s constant?
6.022 x 10^23, the number of particles in one mole of a substance.
What is the molar mass of a substance?
Mass of one mole of any substance, expressed in g/mol.
What is the relationship between molar mass and relative molecular mass?
Molar mass is numerically equal to the relative molecular mass (RMM).
Fill in the blank: The mass of one mole of hydrochloric acid is _______.
36.5 g/mol
How many moles are in 16.0 g of sulfur dioxide (SO2)?
0.25 moles
What is the formula for calculating molarity?
Number of moles of substance in 1L of solution.
What is a solvent?
The liquid in which the solution is formed, usually water.
What is a solute?
The substance dissolved in the solvent.
What is the molarity of 1 mole of NaCl in 1 litre of water?
1 M
What does ppm stand for?
Parts per million.
What is a 5% (w/w) solution?
5.0 g of solute in 95.0 g of solvent.
What is a 7% (w/v) solution?
7.0 g of solute in 100 mL of solvent.
What is the balanced equation for hydrochloric acid (HCl) neutralizing potassium hydroxide (KOH)?
HCl + KOH → KCl + H2O
True or False: The number of moles of reactants is always equal to the number of moles of products in a balanced equation.
True
What is the concentration of HCl neutralized by 54 mL of 0.50 M NaOH?
Depends on the balanced equation.
What is the molarity of 0.5 mole of NaCl in 200 mL of water?
2.5 M
Calculate the ppm concentration of 4g of calcium chloride in 100 mL of water.
40,000 ppm
What is the mass of 0.5 moles of hydrochloric acid?
18.25 g
How many galactose molecules are in 5.23 g of C6H12O6?
0.0285 moles
