Answer: I just took the test. The answer is D! (A single replacement reaction takes place because sodium is more reactive than hydrogen.)
Answer:
20.1 g
Explanation:
The solubility indicates how much of the solute the solvent can dissolve. A solution is saturated when the solvent dissolved the maximum that it can do, so, if more solute is added, it will precipitate. The solubility varies with the temperature. Generally, it increases when the temperature increases.
So, if the solubility is 40.3 g/L, and the volume is 500 mL = 0.5 L, the mass of the solute is:
40.3 g/L = m/V
40.3 g/L = m/0.5L
m = 40.3 g/L * 0.5L
m = 20.1 g
Answer:
(a) oxygen
(b) 154g (to 3sf)
(c) 79.9% (to 3sf)
Explanation:
mass (g) = moles × Mr/Ar
note: eqn means chemical equation
(a)
moles of P = 84.1 ÷ 30.973 = 2.7152 moles
moles of O2 = 85÷2(16) = 2.65625 moles
Assuming all the moles of P is used up,
moles of O2 / moles of phosphorus = 5/4 (according to balanced chemical eqn)
moles of O2 required = 5/4 × 2.7152moles = 3.394 moles (more than supplied which is 2.65625moles)
therefore there is insufficient moles of O2 and the limiting reactant is oxygen.
(b)
moles of P2O5 produced
= 2/5 (according to eqn) × 2.7152
= 1.08608moles
mass of P2O5 produced
= 1.08608 × [ 2(30.973) + 5(16) ]
= 154.164g
= approx. 154g to 3 sig. fig.
(c)
% yield = actual/theoretical yield × 100%
= 123/154 × 100%
= 79.870%
= approx. 79.9% (to 3sf)
Answer:
The most acidic solution had a pH of 3.27.
Explanation:
In order to solve this problem we need to keep in mind that the lower the pH of a solution is, the more acidic the solution is.
If among the pH readings across the measured breakfast drinks, the lowest one was 3.27 (as the problem tells us with the range), then that drink was the most acidic one.
Conversely, the least acidic one had a pH of 3.88.
