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Nadusha1986 [10]
3 years ago
14

Help final grade!!!!!! A B C D

Chemistry
1 answer:
Lelechka [254]3 years ago
7 0
D - a negative ΔH means that energy is released and the reaction is exothermic.
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ANSWER FAST PLZ!!!!!!!!
Rainbow [258]
The answer is

D. I and II only
8 0
3 years ago
A student determined that a 50mL sample of an unknown liquid had a density of 1 g/mL. A 100mL sample of the same liquid would ha
Lyrx [107]

Answer: False

Explanation: The density of the liquid will always be the same, no matter how much of the liquid you have.

For example, the density of the water in a pool is the same density as the water in a small cup.

4 0
3 years ago
How many minutes will it take to plate out 2.19 g of chromium metal from a solution of Cr3+Cr3+ using a current of 55.2 amps in
Kamila [148]

Answer : The time it take to plate out will be, 3.69 minutes.

Explanation :

First we have to calculate the moles of Cr.

\text{Moles of }Cr}=\frac{\text{Mass of Cr}}{\text{Molar mass of Cr}}

Molar mass of Cr = 51.9 g/mol

\text{Moles of }Cr}=\frac{2.19g}{51.9g/mol}=0.0423mol

The cathode half-reaction is,

Cr^{3+}+3e^-\rightarrow Cr

From this we conclude that,

The number of electrons (n)  in the reaction are 3.

The quantity of charge required for the reduction of 1 mole of Cr^{3+} = 3\times F

The quantity of charge required for the reduction of 0.0423 mole of Cr^{3+} = 0.0423\times 3\times F=0.1269F=0.1269\times 96500C=12245.85C

Now we have to calculate the time taken.

We know that,

q=I\times t

t=\frac{q}{I}=\frac{12245.85C}{55.2A}=221.845s=3.69min

Thus, the time it take to plate out will be, 3.69 minutes.

7 0
3 years ago
What is the Ka of a 0.653 m solution of hydrocyanic acid with a ph of 5.47
vredina [299]

Answer:

1.758 x 10⁻¹¹.

Explanation:

∵ pH = - log[H⁺].

∴ 5.47 = -log[H⁺].

log[H⁺] = -5.47.

∴ [H⁺] = 3.388 x 10⁻⁶ M.

∵ [H⁺] = √(Ka.C)

∴ [H⁺]² = Ka.C

<em>∴ Ka = [H⁺]²/C </em>= (3.388 x 10⁻⁶)²(0.653) = <em>1.758 x 10⁻¹¹.</em>

5 0
4 years ago
I know #2 is D. I just need to know why
Allushta [10]

B^2 would not be b*2.

7 0
3 years ago
Read 2 more answers
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