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2 years ago

What volume of hydrogen (in L) is produced

Chemistry

1 answer:

Maslowich2 years ago

7 0

Answer:

52.07 L H₂

Explanation:

Before you can find the volume of H₂, you need to find the moles of H₂. To do this, you need to (1) convert grams Mg to moles (via the atomic mass) and then (2) convert moles Mg to moles H₂ (via the mole-to-mole ratio from equation coefficients).

Atomic Mass (Mg): 24.30 g/mol

1 Mg(s) + 2 HCl(aq) ---> MgCl₂(aq) + 1 H₂(g)
^ ^

56.49 g Mg 1 mole 1 mole H₂
------------------- x ----------------- x -------------------- = 2.32 moles H₂
24.30 g 1 mole Mg

Now that you know the moles of H₂, you need to determine the volume at STP. To do this, you need to set up a proportion comparing the mole value versus the volume. Then, you can cross-multiply to solve for the unknown volume. The final answer should have 4 sig figs to match the given values.

1 mole 2.32 moles
-------------- = -------------------- <----- Set up proportion
22.4 L ? L

(1 mole) x ? L = 52.07 <----- Cross-multiply

? L = 52.07 <----- Divide both sides by 1 mole

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If there are 0.064g of theobromine in a 43g chocolate bar, how many moles of theobromine are there?

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Answer: $3.5\times 10^{-4}$

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3 years ago

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A hydrogen atom with its electron in the n = 6 energy level emits a photon of IR light. Calculate (a) the change in energy of th

geniusboy [140]

Answer:

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(b) The wavelength of the photon is 32841 Å

Explanation:

E = -kz²/n²

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E = hc/λ

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3 years ago

How many moles of oxygen are needed to make 12 moles of magnesium oxide ?

Artemon [7]

Answer:

6 moles of oxygen are needed to make 12 moles of magnesium oxide.

Explanation:

First of all you should know that the balanced chemical equation is:

2 Mg + O₂ → 2 MgO

The rule of three or is a way of solving problems of proportionality between three known values and an unknown value, establishing a relationship of proportionality between all of them. That is, what is intended with it is to find the fourth term of a proportion knowing the other three. Remember that proportionality is a constant relationship or ratio between different magnitudes.

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c ⇒ x

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$x=\frac{c*b}{a}$

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moles of oxygen= 6

<u><em>6 moles of oxygen are needed to make 12 moles of magnesium oxide.</em></u>

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