The equation for density is mass/volume. Make sure your units match what is given in the problem.
The answer is $2.89.
Since it’s asking for the unit price of one gallon and you have the total ($34.68 and 12 gallons), you would divide $34.68 from 12, which gives you $2.89.
34.68/12 = 2.89
The answer is (D) microscopic. You can remember this, because the name is very close to "microscope," an instrument used to greatly magnify and observe tiny organisms and objects.
One mole of Na2SO4 is 6.022 * 10^(23) molecules. We can divide this into the quantity in the question to find a value of 1.5/6.022 = 0.2491 moles. Rounded to two significant figures and put in scientific notation, we can rewrite this quantity as 2.5 * 10^(-1) moles
Mercury (ii) oxide is made up of mercury and oxygen. The total mass of mercury (ii) oxide is 14.2 g, after decomposition 13.2 g of mercury were formed, therefore the mass of oxygen 1 g (14.2 g -13.2 g).
Percentage of oxygen = (1/14.2)×100 = 7.04%
Percentage of mercury = (13.2/14.2) × 100 = 92.96%
Therefore, percentage composition of the compound, oxygen is 7.04% and mercury is 92.96%.