The correct question is as follows:
How do you convert from grams to moles of a substance
1. Divide by the molar mass
2. Subtract the molar mass
3. Add the molar mass
4. Multiple by the molar mass
Answer: In order to convert from grams to moles of a substance divide by the molar mass.
Explanation:
The number of moles of a substance is the mass of substance in grams divided by its molar mass.
The formula to calculate moles is as follows.

This means that grams are converted to moles when grams is divided by molar mass.
Thus, we can conclude that in order to convert from grams to moles of a substance divide by the molar mass.
No atoms are lost or made during the chemical reaction so the total mass of the products is equal to the total mass of the reactants. In an atom, protons and neutrons contribute to the mass and since the number of them doesn’t change, the mass doesn’t either.
Answer:
The density of acetic acid at 30°C = 1.0354_g/mL
Explanation:
specific gravity of acetic acid = (Density of acetic acid at 30°C) ÷ (Density of water at 30°C)
Therefore, the density of acetic acid at 30°C = (Density of water at 30°C) × (Specific gravity of acetic acid at 30°C)
= 0.9956 g/mL × 1.040
= 1.0354_g/mL
Specific gravity, which is also known as relative density, is the ratio of the density of a substance to the density of a specified standard substance.
Generally the standard substance of to which other solid and liquid substances are compared is water which has a density of 1.0 kg per litre or 62.4 pounds/cubic foot at 4 °C (39.2 °F) while gases are normally compared with dry air, with a density of 1.29 grams/litre or 1.29 ounces/cubic foot under standard conditions of a temperature of 0 °C and one standard atmospheric pressure
I think the correct answers are X2Y and X3Y, X2Y5 and X3Y5, and X4Y2 and X3Y,
for the following reason:
If you look at the combining masses of X and Y in
each of the two compounds,
The first compound contains 0.25g of X combined with
0.75g of Y
so the ratio (by mass) of X to Y = 1 : 3
The second compound contains 0.33 g of X combined with
0.67 g of Y
so the ratio (by mass) of X to Y = 1 : 2
Now, you suppose to prepare each of these two
compounds, starting with the same fixed mass of element Y ( I will choose 12g
of Y for an easy calculation!)
The first compound will then contain 4g of X and 12g
of Y
The second compound will then contain 6g of X and
12g of Y
<span>The ratio which combined
the masses of X and the fixed mass (12g) of Y
= 4 : 6
<span>or 2 : 3 </span>
So, the ratio of MOLES of X which combined with the
fixed amount of Y in the two compounds is also = 2 : 3 </span>
The two compounds given with the plausible formula must therefore contain
the same ratio.