Answer:

Explanation:
We need to use the formula for heat of vaporization.

Identify the variables.
- The heat absorbed by the evaporating water is the <u>latent heat of vaporization. </u>For water, that is 2260 Joules per gram.
- Q is the energy, in this problem, 50,000 Joules.
- m is the mass, which is unknown.

Substitute the values into the formula.

We want to find the mass. We must isolate the variable, m.
m is being multiplied by 2260 J/g. The inverse operation of multiplication is division. Divide both sides by 2260 J/g.


Divide. Note that the Joules (J) will cancel each other out.


Round to the nearest whole number. The 1 in the tenth place tells us to leave the number as is.

The mass is about 22 grams, so choice B is correct.
Answer:
Isotopes of an element are atoms of the same element that have different number of neutrons.
Ethanol will evaporate first because it is more volatile or has a lower boiling point than water.
Answer:
3.0 L of NH₃
Solution:
The equation is as follow,
N₂ + 3 H₂ → 2 NH₃
According to equation,
67.2 L (3 mole) H₂ at STP produces = 44.8 L (3 mole) of NH₃
So,
4.50 L of H₂ will produce = X L of NH₃
Solving for X,
X = (4.50 L × 44.8 L) ÷ 67.2 L
X = 3.0 L of NH₃