Answer:
Since 2H₂ + O₂ ---> 2H₂O
We need 2 moles of hydrogen for each mole of oxygen
So, we need 2(6) = 12 moles of H₂ but since we only have 10 moles,
H₂ is the limiting reagent
So since 2 moles of H₂ gives 2 moles of water,
10 moles of H₂ will give rise to 10 moles of Water with 1 mole of remaining oxygen
Q1. The answer is 3 minutes.
Let's first calculate the remaining amount in percent:
If 960g is 100 percent (starting amount), 30 g is how many percents:
960 g : 100% = 30 g : x
x = 30 g * 100% / 960 g = 3.125% = 0.03125
Now, using the formula to calculate the number of half-lives:
(1/2)ⁿ = x,
where
x is the remaining amount: x = 0.03125
n is the number of half-lives
1/2 stands for half-life.
(1/2)ⁿ = 0.03125
⇒ n*log(1/2) = log(0.03125)
n = log(0.03125)/log(1/2) = log(0.03125)/log(0.5) = -1.505/-0.301 ≈ 5
The number of half-lives is 5.
Now, <span>the number of half-lives (n) is a quotient of total time elapsed (T) and length of half-life (L):
n = T/L
We know:
n = 5
T = 15 min
L = ?
Thus
L = T/n
L = 15 min/5 = 3 minutes
Q2. Filtration should be chosen.
Filtration and distillation are used to separate mixtures - filtration for the separation of heterogeneous mixtures and </span>distillation for the separation of homogeneous mixtures. Imagine that your pile of soil is a mixture. It consists of different components (the leaves, acorns, twigs), so it is the heterogeneous mixture. Therefore, to separate the leaves, acorns, twigs you will use filtration.
Answer:
Add water to 29.22 grams of salt until you get 1 liter of volume, stir it until the salt completely dissolves and mixes and voila! you will have a 0.5 M NaCl solution.
:)
The answer to that question is B
