Answer: 3.44 kg
Explanation: Formula of Aluminium oxide is Al2O3
Molar mass M = 2·26.98 + 3·16 = 101.96 g/mol
m-% of Al is 2·26.98 / 101.96 = 52.92 % = 0.5292
Mass of Al in Aluminium oxide is 0.5292 · 6.50 kg
Answer : The mass of aluminium (Al) is 0.413 g
Solution : Given,
Volume of
at STP = 513 ml = 0.513 L ( 1 L = 1000 ml )
Molar mass of aluminium = 26.98 g/mole
First we have to calculate the moles of
.
At STP,
1 mole occupies 22.4 L volume
now, 0.513 L gives
moles of 
The moles of
= 0.0229 moles
The Net balanced chemical reaction is,

From the balanced chemical reaction, we conclude that
2 moles of Aluminium (Al) produces 3 moles of hydrogen gas
Now the number of moles of aluminium required in 0.0229 moles of hydrogen gas =
= 0.0153 moles
Now we have to calculate the mass of aluminium.
Mass of aluminium = number of moles × Molar mass = 0.0153 moles × 26.98 g/mole = 0.413 g
The mass of aluminium required is 0.413 g.
Answer:
Carbon is dull, have a low density, and are poor conductors of heat.
Explanation:
Carbon is a non-metal, therefore bearing properties of a non-metal element.
MCu: 63,5 g/mol
4 × mCu = 63,5×4 = 254 g
254g ------ 0,39%
Xg ---------- 100%
X = (254×100)/0,39
X = 65128,2 g/ mol <<<< molar mass
Answer: weigh is m = n × M = 2.87 mol × 58.44 g/mol
Explanation: mass = amount of substance × molar mass
M((NaCl) = 22.99 +35.45