L2 - Solutions and dilutions 1

Question 1

Name 3 places in which solutions and dilutions are applied to the field of Biomedical Sciences.

Answer 1

1) saline - 0.9% - that’s 9g of NaCl per 100ml
2) intravenous infusion - 5% w/v glucose - weight per volume - 5g of glucose for every 100ml
3) IV Drip 500mL

Question 2

Name an application of solutions in a muscular injury.

Answer 2

Kool Pak - contains urea and water

Question 3

Define mass.

Answer 3

A measure for the amount of matter in an object

Question 4

Define weight.

Answer 4

The force of attraction between the object and its surroundings.

Question 5

What’s the formula that connects weight and mass?

Answer 5

W = mg

Question 6

What’s the formula that connects force and mass?

Answer 6

F = ma

Question 7

What makes weight different to mass?

Answer 7

Weight changes depending on the change of gravitational attraction with the change of geographic location. The mass stays the same.

Question 8

Define Mole.

Answer 8

mole is an SI unit for the amount of a chemical species normalised to pure carbon.
1 mol of 12C is 12g

Question 9

Define Avagadro’s constant.

Answer 9

Avagadro’s constant is the number of atoms or molecules in one mole of a substance.
6.022*10^23

Question 10

Q: Given that the molecular weight of carbon is 12.01g/mol …. How many moles are there in 31.87g of carbon?

Answer 10

2.654 moles

Question 11

Q: How many atoms are in 31.87g of carbon given that there are 2.654 moles expressed in the correct scientific notation and 2dp?

Answer 11

1.60*10^24 carbon atoms

Question 12

What formula links molarity and volume?

Answer 12

Molarity(M) = Moles of solute (mol) / Litres of solution (L)
SI unit - Mol/L

Question 13

What two things does molarity relate?

Answer 13

Molarity relates the amount of moles of a solute per litre of solution.

Question 14

Q: Using distilled water as the solvent, how can we make 100mL of 0.10M solution of CuSo4 - Copper sulfate?
the molecular weight of copper sulfate is 249.69g/mol

Answer 14

moles of copper sulfate - 0.01 moles
the weight of copper sulfate - 2.4969

Question 15

Q: lab calculation
“We have run out of cell culture buffer! Can you make up a solution for me, please?
NaHCO3 , 0.035M , (250mL)”
USEFUL FORMULA :
Mass compound(g) = Molarity(M) * Volume(L) * Molar mass (g/mol)

Answer 15

its meant to be
0.035 * 0.250 * 84.01
0.735g of NaHCO3

Question 16

what balance type corresponds to what readability? - weighing scale
top pan
analytical
semi-micro
micro

Answer 16

top pan - 0.01g to 0.1g
analytical - 0.0001g - 0.1mg
semi-micro - 1-10μg
micro - 0.1μg

Question 17

lab water types and their uses c
check iPad for ss