concentrations of solutions

Question 1

what is concentration

Answer 1

concentration refers to the amount of a substance in a defined space

Question 2

what is the formula for concentration

Answer 2

concentration = mass of solute / volume of solvent

Question 3

what is the units for this formula

Answer 3

concentration = g/dm3
mass of solute = g
volume of solvent = dm3

Question 4

whats the concentration, in g/dm3, of a solution with 15g of salt in 500 cm3

Answer 4

convert the volume (500cm3) to dm3 by dividing by 1000
500cm3 /1000 = 0.5dm3
concentration = 15/0.5 = 30 g/dm*3

Question 5

rearrange to make mass the subject

Answer 5

mass = concentration X volume

Question 6

what is the mass of solute in 0.25 dm3 of solution with a concentration of 32 g/dm3

Answer 6

mass = 0.25 X 32
= 8g

Question 7

calculate the concentration of a solution that contains 0.6 g of salt in 15cm*3 of solvent

Answer 7

15cm3 / 1000 = 0.015dm3
0.6 / 0.015
= 40 g/dm*3