these questions are related to each other please help me on

these questions are related to each other. please help me on these questions.

1. you have a moecule with a MW of 300. how many grams do you need to make one ml of 100mM solution?

2. you have a 30 mg/ml solution of a molecule with a MW of 300 what is the molarity of this 30 mg/ml solution?

3. how many ul( microliter) of the above 30mg/ml solution do you need to make 1 ml of 1mM dilution?

Solution

these questions are related to each other. please help me on these questions.

1. you have a molecule with a MW of 300. how many grams do you need to make one ml of 100mM solution?

Answer:

For a molecule with a MW of 300,

Grams to weigh = desired volume x desired molarity x Molar mass

= 0.001 L x 0.1M x 300

= 0.03g

2. you have a 30 mg/ml solution of a molecule with a MW of 300 what is the molarity of this 30 mg/ml solution?

Answer:

Molarity = (Grams in weight )/(Volume x molar mass)

= (30g)/(0.01L x 300)

=10M

3. how many ul( microliter) of the above 30mg/ml solution do you need to make 1 ml of 1mM dilution?

Answer:

Stock = 10 M

Required = 1mM = 0.001M

Volume= 1 mL

C1V1= C2V2

(stock)   (required)

V1=C2V2/C1

V1 = (0.01M X 1 mL)/ 10M

= 0.001 mL

=1uL

1uL of 10M stock + 999 uL of H2O gives 1mM solution