Answer: 61%
The reaction equation should be
CaF2 + H2SO4 → 2HF + CaSO4
For every 1 molecule CaF2 used, there will be 2 molecules of HF formed. The molecular mass of CaF2 is 78/mol while the molecular mass of HF is 20g/mol. If the yield is 100%, the amount of HF formed by 112g CaF2 would be: 112g/(78g/mol) * 2 * (20g/mol)=57.43g
The percentage yield of the reaction would be: 35g/57.43g= 60.94%
The mass number of an atom is obtained by totalling up the number of protons and neutrons there are for that atom.
Answer:
Na
Explanation:
To find the limiting reactant we must first write the balanced chemical reaction. It must be correctly balanced so that we can find the proper mole ratios.
2 Na + H₂ → 2 NaH
After this we will convert our measurements to moles. For mass we do this by dividing by the molar mass.
6.75g ÷ 22.99 = 0.294mol Na
3.03g ÷ 2.02 = 1.50mol H₂
Now that we have the moles of each of the reactants, we can multiply them by their mole ratio with a reactant.
0.294mol Na ×
= 0.294mol NaH
1.50mol H₂ × 2/1 = 3.00mol NaH
Na is our limiting reagent because it makes the smaller amount of moles.
The heat of vaporization is =924.71 j/g
<em><u>explanation</u></em>
<u><em> </em></u>Heat of vaporization is amount of heat require to vaporize 1 gram of a substance.
Heat of vaporization required is therefore=8720 joules/9.43 grams=924.71 j/g
Answer:
₉₂U²³⁸ → ₉₀Th²³⁴ + ₂He⁴
Explanation:
Alpha beta and gamma radiations are the examples of ionizing radiations. When an atom is an excited state and having high energy, the atom is in unstable state. The excess of energy is released by the atom to get the stability. The released energy is in the form of radiations which may include alpha, beta, gamma, X-ray etc.
Alpha decay:
Alpha radiations are emitted as a result of radioactive decay. The atom emit the alpha particles consist of two proton and two neutrons. Which is also called helium nuclei. When atom undergoes the alpha emission the original atom convert into the atom having mass number less than 4 and atomic number less than 2 as compared to parent atom the starting atom.
Properties of alpha radiation:
Alpha radiations can travel in a short distance.
These radiations can not penetrate into the skin or clothes.
These radiations can be harmful for the human if these are inhaled.
These radiations can be stopped by a piece of paper.
₉₂U²³⁸ → ₉₀Th²³⁴ + ₂He⁴