18. The lighter, outer part of the shadow is called til 9. The color of the moon during a lunar eclipse depends on the amount of
2 answers:
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Answer:
0.44g
Explanation:
Given parameters:
Mass of magnesium hydroxide = 0.645g
Solution
The balanced reaction equation is shown below:
Mg(OH)₂ → MgO + H₂O
From the equation above, we see that the number of atoms are conserved.
To find the mass of magnesium oxide produced, we find the number moles of the decomposed magnesium hydroxide first:
Molar mass of Mg(OH)₂ = 24 + 2(16+1) = 58g/mol
Number of moles of Mg(OH)₂ =
=
= 0.011mole
Now, from the balanced equaiton, we know that:
1 mole of Mg(OH)₂ produces 1 mole of MgO
Therefore, 0.011mole of Mg(OH)₂ will produce 0.011mole of MgO
so mass of MgO = number of moles of MgO x molar mass of MgO
Molar mass of MgO = 24 + 16 = 40g/mol
mass of MgO = 0.011 x 40 = 0.44g
Answer: 136 g of must be reacted to inflate an air bag to 70.6 L at STP.
Explanation:
Using ideal gas equation:
P= pressure of nitrogen gas = 1 atm (at STP)
V =volume of nitrogen gas = 70.6 L
n = number of moles of nitrogen gas = 1 atm (at STP)
R = gas constant = 0.0821 Latm/Kmol
T = temperature of nitrogen gas = 273 K (at STP)
For the balanced chemical reaction:
3 moles of nitrogen are produced by = 2 moles of
3.14 moles of nitrogen are produced by = moles of
Mass of = Moles × Molar mass = 2.09 mole × 65 g/mol = 136 g