Chemistry Help...Multi Choice Questions?

Question

35. What is the concentration of the sodium ion, Na+ in a 0.300 M Na2CO3?
a)0.200 M
b) 0.300 M
c)0,600 M
d) 0.900 M

36. A 0.0010 M HCN solution has a ka = 6 x10^-10. Which terms describe this acid solution?
a)weak and dilute
b)strong and dilute
c)concentrated and weak
d) concentrated and strong

37. What is the ksp expression for strontium carbonate, SrCO3?

38. Ehat voume , in cm^3, of 0.100 M NaOH is required to beutralize 40.0 cm^3 of 0.100 M H2SO4?
a) 20.0
b) 40.0
c) 80.0
d)100

39. What must be true about this spontaneous reaction?
2Cr^2 + I2 > 2Cr^3 + 2I-
a) I2 is oxidized
b) Chromium ions are reduced
c) More electrons are lost than gained.
d) The standard potential is positive.

40. If 60 g of each solute is mixed with seperate 100 g sample of water at 20 C which forms unsaturated solutions?
a) all would be unsaturated.
b) only KBr would be unsaturated
c) only KNO3 would be unsaturated
d) NaCL, KCl, and KBr would be unsaturated

Answer 1

35. c. Two ions of Na+ produced per molecule dissolved, so the concentration will be doubled.

36. a. Weak and dilute. A weak acid has a Ka value, a strong acid does not. And a 0.001 M solution is quite dilute.

37. Ksp = [Sr2+][CO32-]

38. c. 80 cm^3 Sulfuric acid is diprotic, so it takes twice as much hydroxide to neutralize it in terms of moles. Since the molarities are equal, the volume has to be double.

39. d. For it to be spontaneous, the potential has to be positive.

40. Don't have solubilities handy, but I know NaCl would not be unsaturated at that level, so a and d aren't possible. According to wikipedia, KNO3's solubility is 35.7 g/ 100 ml, so it would not be unsaturated either. KBr's solubility is 53 g/ 100 ml of solution, so you could dissolve 53 g in 47 g of water, so a 60 in 100 would be unsaturated. B is the answer.