3- Quantitative chemistry

Question 1

what does the law of conservation of mass state

Answer 1

The law of conservation of mass states that no atoms are lost or made in a chemical reaction

Mass of reactants = massnof products

Question 2

Why might changed in mass be seem in a non-enclosed system

Answer 2

• Reactants from the environment can entre the sytsem
• ractants and products can escape into the environment (commonly gases)

Question 3

uncertainty formula

Answer 3

range/2

Question 4

what is the avogadro constant

Answer 4

how many particles in a mol

Question 5

what is the limiting reactant

Answer 5

the reactant that is fully used up

Question 6

equation used by limitig reactant

Answer 6

mol of limiting reactant x Relative formula mass of product requested

Question 7

what is concentration

Answer 7

tells us the mass of a solute in a given volume of solution

Question 8

what is a solute

Answer 8

a chemical dissolved in solvent

Question 9

unit of concentration

Answer 9

g/dm^3

Question 10

equation for concentration

Answer 10

concentration = mass/volume

Question 11

if we Increase the mass of solute and keep the volume the same, we ________ the concentration

Answer 11

increase

Question 12

if we increase the volume of solution and keep the mass of the solute the same, then we ________ the concentration

Answer 12

decrease

Question 13

equation for percentage by mass

Answer 13

% by mass - total atomic mass of atoms/ relative formula mass of compound x100

Question 14

quation to calculate the number of atoms in a massof an element

Answer 14

moles = mass/Ar (Mr for compounds)