module 12.3- concentration of solutions

Question 1

what does strength refer to?

Answer 1

how chemically reactive a substance is

Question 2

what happens when acids dissolve in water and release hydrogen ions?

Answer 2

the slightly negative end of the water molecule is attracted to the hydrogen ion and a new ion H3O (hydronium ion is formed

Question 3

what is the process of ionisation?

Answer 3

when acids form ions in water

*strong acids (eg HCl) ionise completely in water to form H3O and Cl ions
-> in contrast, only a small proportion of ethanoic acid molecules (weak acid) have ionised to form H3O and ethanoate ions

Question 4

an acid is a… and a base is a…

Answer 4

proton donor and proton acceptor

Question 5

what is a standard solution?

Answer 5

solution that has an accurately known concentration

Question 6

aliquot definition

Answer 6

volume dispensed from a pipette

Question 7

calibration mark definition

Answer 7

line drawn on the pipette/standard volumetric flask: when bottom of meniscus sits exactly on this line= precise volume

Question 8

what is the process of preparing a dilute solution from a more concentrated solution?

Answer 8

1. pipette used to take aliquot from sol. of known concentration
2. aliquot transferred to second volumetric flask
3. diluted solution prepared by adding distilled water up to the calibration mark

Question 9

what is the solution formula?

Answer 9

c1V1=c2V2

c1- initial concentration
V1- initial volume
c2- final concentration
V2- final volume

Question 10

formula of concentration (g/L)?

Answer 10

concentration (g/L)= mass volume (g)/volume solution (L)

Question 11

what is ppm?

Answer 11

parts per million
*equivalent to mg/kg or mg/L