Answer:
1 M
Explanation:
The molarity of a solution, M, is a measure of the concentration of that solution and it refers to the number of moles of solute (mol) per liter (L) of solution. The molarity (M) can be calculated using the formula:
M = number of moles (n) /volume (V)
In this question, a 500 ml aqueous solution of Na3PO4 was prepared using 82g of the solute.
Molar mass of Na3PO4 = 23(3) + 15 + 16(4)
= 69 + 31 + 64
= 164g/mol
Mole = mass/molar mass
mole = 82/164
mole = 0.5 mol
Volume in Litres (L) = 500 ml ÷ 1000 = 0.500L
Therefore, Molarity (M) = 0.5/0.500
Molarity = 1 M or 1 mol/L
Energy released from changing the phase of a substance from the gas phase to liquid phase can be calculated by using the specific latent heat of vaporization. The heat of fusion of water at 0 degrees Celsius is 40.7 kJ/mol. Calculation are as follows:<span> </span>
Energy = 27.9 g (1 mol / 18.02 g) x 40.7 kJ/mol
Energy = 63.09 kJ
Fire is actually a chemical reaction. It's an oxidation reaction to be specific. When wood gets hot enough (the part of the wood that is burning) the large hydrocarbons break down to charred solids and a gas. The gas is what reacts with oxygen in the atmosphere to produced light, CO2 and H2O.
Answer:
the volume occupied by 3.0 g of the gas is 16.8 L.
Explanation:
Given;
initial reacting mass of the helium gas, m₁ = 4.0 g
volume occupied by the helium gas, V = 22.4 L
pressure of the gas, P = 1 .0 atm
temperature of the gas, T = 0⁰C = 273 K
atomic mass of helium gas, M = 4.0 g/mol
initial number of moles of the gas is calculated as follows;
The number of moles of the gas when the reacting mass is 3.0 g;
m₂ = 3.0 g
The volume of the gas at 0.75 mol is determined using ideal gas law;
PV = nRT
Therefore, the volume occupied by 3.0 g of the gas is 16.8 L.
