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2 years ago

What mass of zinc (molar mass 65.4 g moll) does it take to produce 0.50 mole of H2(g)?

Chemistry

1 answer:

Hatshy [7]2 years ago

4 0

Answer:

32.7 g of Zn

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

Zn + 2HCl —> ZnCl₂ + H₂

From the balanced equation above,

1 mole of Zn reacted to produce 1 mole of H₂

Next, we shall determine the number of mole of Zn required to produce 0.5 mole of H₂. This can be obtained as follow:

From the balanced equation above,

1 mole of Zn reacted to produce 1 mole of H₂.

Therefore, 0.5 mole of Zn will also react to produce to 0.5 mole of H₂.

Thus, 0.5 mole of Zn is required.

Finally, we shall determine the mass of 0.5 mole of Zn. This can be obtained as follow:

Mole of Zn = 0.5 mole

Molar mass of Zn = 65.4 g/mol

Mass of Zn =?

Mass = mole × molar mass

Mass of Zn = 0.5 × 65.4

Mass of Zn = 32.7 g

Thus, 32.7 g of Zn is required to produce 0.5 mole of H₂.

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The rate constant for the second-order reaction: 2NOBr(g) → 2NO(g) + Br2(g) is 0.80/(M · s) at 10°C. Starting with a concentrati

a_sh-v [17]

Answer : The concentration of NOBr after 95 s is, 0.013 M

Explanation :

The integrated rate law equation for second order reaction follows:

$k=\frac{1}{t}\left (\frac{1}{[A]}-\frac{1}{[A]_o}\right)$

where,

k = rate constant = $0.80M^{-1}s^{-1}$

t = time taken = 95 s

[A] = concentration of substance after time 't' = ?

$[A]_o$ = Initial concentration = 0.86 M

Now put all the given values in above equation, we get:

$0.80=\frac{1}{95}\left (\frac{1}{[A]}-\frac{1}{(0.86)}\right)$

[A] = 0.013 M

Hence, the concentration of NOBr after 95 s is, 0.013 M

4 0

3 years ago

Given 6.98 x 10 4 power grams of iron, calculate the moles of iron present

KiRa [710]

Answer:

1249.88 mol.

Explanation:

∵ no. of moles of Fe = mass of Fe/atomic weight of Fe.

<em>∴ no. of moles of Fe </em>= (6.98 x 10⁴ g)/(55.845 g/mol) = <em>1249.88 mol.</em>

6 0

3 years ago

0.10 M potassium chromate is slowly added to a solution containing 0.20 M AgNO3 and 0.20 M Ba(NO3)2. What is the Ag+ concentrati

erastova [34]

Answer:

$[Ag^{+}]=4.2\times 10^{-2}M$

Explanation:

Given:

[AgNO3] = 0.20 M

Ba(NO3)2 = 0.20 M

[K2CrO4] = 0.10 M

Ksp of Ag2CrO4 = 1.1 x 10^-12

Ksp of BaCrO4 = 1.1 x 10^-10

$BaCrO_4 (s)\leftrightharpoons Ba^{2+}(aq)\;+\;CrO_{4}^{2-}(aq)$

$Ksp=[Ba^{2+}][CrO_{4}^{2-}]$

$1.2\times 10^{-10}=(0.20)[CrO_{4}^{2-}]$

$[CrO_{4}^{2-}]=\frac{1.2\times 10^{-10}}{(0.20)}= 6.0\times 10^{-10}$

Now,

$Ag_{2}CrO_4(s) \leftrightharpoons 2Ag^{+}(aq)\;+\;CrO_{4}^{2-}(aq)$

$Ksp=[Ag^{+}]^{2}[CrO_{4}^{2-}]$

$1.1\times 10^{-12}=[Ag^{+}]^{2}](6.0\times 10^{-10})$

$[Ag^{+}]^{2}]=\frac{1.1\times 10^{-12}}{(6.0\times 10^{-10})}= 1.8\times 10^{-3}$

$[Ag^{+}]=\sqrt{1.8\times 10^{-3}}=4.2\times 10^{-2}M$

So, BaCrO4 will start precipitating when [Ag+] is 4.2 x 1.2^-2 M

7 0

3 years ago

Atomic radius increases as you move down a group of elements.

raketka [301]

Yes, the atomic radius increases as you move down a group of elements. this is true
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3 0

3 years ago

Cytoplasm is a mixture of what two things?

alexira [117]

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Movement of calcium ions in and out of the cytoplasm is a signaling activity for metabolic processes.[2]

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3 years ago