Question

1) A 10.0 milliliter sample of NaOH (aq) is neutralized by 40.0 milliliters of 0.50 M HCl. What is the molarity of the NaOH (aq)?

1. 1.0 M
2. 2.0 M
3. 0.25 M
4. 0.50 M

2) A 10.0-gram sample of H2O(ℓ) at 23.0°C absorbs 209 joules of heat. What is the final temperature of the H2O(ℓ) sample?
(1) 5.0°C (3) 28.0°C
(2) 18.0°C (4) 50.0°C

Answer 1

1st question) 209 = 10 x 4.184 x (Tfinal - 23 degrees Celsius)
you get Tfinal = 28 degrees Celsius

2nd question) As for your second question, we just use M1V1 = M2V2,

M of NaOH x 10mililiter NaOH = 0.5M HCl x 40 mililiter of HCl
M of NaOH = 2M, that's your answer