Moles = Mass(g) / ar
Moles of phosphorus = 0.859 / 31
= 0.0277096774
1 mole = 6.02 × 10^23
Atoms of phosphorus = 0.0277096774 × 6.02×10^23
=ans.
sorry i cant do the calculation. I dont have a calculator with me.
Answer:
The sun uses nuclear fusion reactions to generate heat.
Explanation:
It is true from the given choices that the sun uses nuclear fusion reactions to generate heat.
The heat that accompanies nuclear fusion reactions is very huge. In fact this is the source of energy for the whole solar system.
During a nuclear fusion reaction, small atomic nuclei combines to form larger ones.
This combination results in a series of chain reactions that releases energy.
Phase transitions is when a substance go through a change in its physical state, for example, solid to liquid, liquid to gas, etc. Energy in this case must be absorbed or released, and not necessarily it will be seen a change of temperature in this case. Mathematically, we calculate the energy released or absorbed by using the molar enthalpy of vaporization or molar enthalpy of fusion, as we can see in the following formulas:
ΔH = m*ΔHvap
ΔH = m*ΔHfusion
So phase transition is the energy required for a substance to change the physical state.
Answer:
The percentage by mass of water in magnesium sulfate heptahydrate is 51.2 %
Explanation:
<u>Step 1:</u> Data given
Molar mass of MgSO4*7H2O = 246.5 g/mol
Molar mass of H2O = 18.02 g/mol
Molar massof MgSO4 = 120.37 g/mol
<u>Step 2:</u> Calculate % water in magnesium sulfate heptahydrate
Since we have 7 molecules of water in the heptahydrate, we will divide the molar mass of 7 molecules water by the molar mass of the heptahydrate.
m%(H2O) = (7*18.02)/ 246.5
m%(H2O) = (126.14 /246.5)*100%
m%(H2O) = 51.2 %
To controle this we will calculate the mass % of MgSO4
m%(MgSO4) = (120.37/ 246.50)*100%
m%(MgSO4) = 48.8%
51.2 + 48.8 = 100%
The percentage by mass of water in magnesium sulfate heptahydrate is 51.2 %