Answer:
39.7 %
Explanation:
magnesium + oxygen ⟶ magnesium oxide
10.57 g 6.96 g 17.53 g
According to the <em>Law of Conservation of Mass</em>, the mass of the product must equal the total mass of the reactants.
Mass of MgO = 10.57 + 6.96
Mass of MgO = 17.53 g
The formula for mass percent is
% by mass = Mass of component/Total mass × 100 %
In this case,
% O = mass of O/mass of MgO × 100 %
Mass of O = 6.96 g
Mass of MgO = 17.53 g
% O = 6.96/17.53 × 100
% O = 0.3970 × 100
% O = 39.7 %
Answer:
0.13 M
Explanation:
The reaction equation is;
NaOH(aq) + KHC8H4O4(aq) ------> KNaC8H4O4(aq) + H2O(l)
Molar mass of KHP = 204.22 g/mol
Amount of KHP= mass/ molar mass = 0.3365 g/204.22 g/mol = 1.65 × 10^-3 moles
n= CV
Where;
C= concentration
V= volume in dm^3
n= number of moles
C= n/V = 1.65 × 10^-3 moles × 1000/250 = 6.6 × 10^-3 M
If 1 mole of KHP reacts with 1 mole of NaOH
1.65 × 10^-3 moles of KHP will react with 1.65 × 10^-3 moles of NaOH
From
n= CV
We have that only 12.44 ml of NaOH reacted
C= n/V = 1.65 × 10^-3 moles × 1000/12.44
C= 0.13 M
At the equivalence point, the KHP solution turned light pink.
For every, 3 Br- ions, 1 Al3+ ion reacts to form AlBr3.
Convert 16.2g of aluminum to moles:
16.2g Al / 27.0g per mol = 0.60 mols.
Based on the above ratio, 0.60 mols of Al will react with 1.8 mols of Br.
Convert 1.8 mols of Br to its mass:
1.8 mols Br × 79.9g per mol = 143.82g of Br.
A) Potassium
Potassium contains the six chemical elements that make it an alkali metal?
Answer:
P₂ = 20.5 torr
Explanation:
Given data:
Volume of tank = 15.0 L
Pressure of tank = 8.20×10⁴ torr
Final volume of tank = 6.00×10⁴ L
Final pressure = ?
Solution:
The given problem will be solved through the Boly's law,
"The volume of given amount of gas is inversely proportional to its pressure by keeping the temperature and number of moles constant"
Mathematical expression:
P₁V₁ = P₂V₂
P₁ = Initial pressure
V₁ = initial volume
P₂ = final pressure
V₂ = final volume
Now we will put the values in formula,
P₁V₁ = P₂V₂
8.20×10⁴ torr × 15.0 L = P₂ × 6.00×10⁴ L
P₂ = 8.20×10⁴ torr × 15.0 L / 6.00×10⁴ L
P₂ = 123×10⁴ torr.L/ 6.00×10⁴ L
P₂ = 20.5 torr
