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3 years ago

What's the answer to this question?

Chemistry

2 answers:

RoseWind [281]3 years ago

5 0

The answer is b because it’s 124 degrees

Lena [83]3 years ago

4 0

The answer is B- 124 degrees

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How many significant figures are in the number 20300?

arlik [135]

Answer:

There are three significant figures in the number 20300

3 0

4 years ago

Ammonia is formed according to the reaction below. A chemist mixes 21 grams of nitrogen gas and 18 grams of hydrogen gas in a 2.

Rama09 [41]

Answer : The mass of hydrogen gas consumed will be, 4.5 grams

Explanation : Given,

Mass of $N_2$ = 21 g

Mass of $H_2$ = 18 g

Molar mass of $N_2$ = 28 g/mole

Molar mass of $H_2$ = 2 g/mole

First we have to calculate the moles of $N_2$ and $H_2$ .

$\text{Moles of }N_2=\frac{\text{Mass of }N_2}{\text{Molar mass of }N_2}=\frac{21g}{28g/mole}=0.75moles$

$\text{Moles of }H_2=\frac{\text{Mass of }H_2}{\text{Molar mass of }H_2}=\frac{18g}{2g/mole}=9moles$

Now we have to calculate the limiting and excess reagent.

The balanced chemical reaction is,

$N_2(g)+3H_2(g)\rightarrow 2NH_3(g)$

From the given balanced reaction, we conclude that

As, 1 mole of $N_2$ react with 3 moles of $H_2$

So, 0.75 moles of $N_2$ react with $3\times 0.75=2.25$ moles of $H_2$

From this we conclude that, $H_2$ is an excess reagent because the given moles are greater than the required moles and $N_2$ is a limiting reagent because it limits the formation of product.

The moles of hydrogen gas consumed = 2.25 mole

Now we have to calculate the mass of hydrogen gas consumed.

$\text{Mass of }H_2=\text{Moles of }H_2\times \text{Molar mass of }H_2$

$\text{Mass of }H_2=(2.25mole)\times (2g/mole)=4.5g$

Therefore, the mass of hydrogen gas consumed will be, 4.5 grams

5 0

4 years ago

Given the reaction: Ca(s) + Cu2+ (aq) - Ca2+(aq) + Cu(s)

Inga [223]

Answer:

Explanation:

Copper 2+ to copper solid is the correct reduction half reaction as it involves electron gain

7 0

4 years ago

Read 2 more answers

B. The heat of reaction for the process described in (a) can be determined by

julsineya [31]

Answer: I believe the 1st and 3rd reactions are better obtained through reference sources and the 2nd and 4th are easiest and safest to measure in the laboratory.

Explanation:

I am also working on this Pre-lab right now, and I looked back at the first question to help get my answer. In the first question (a), it is noted that ammonia gas and gaseous hydrochloric acid are both potentially dangerous in gaseous form. I saw that both the 1st and 3rd reactions contained noxious gases (I knew this because there was a (g) in both of these reactions). Using the knowledge from the first question that the noxious gases were potentially dangerous, I assumed that those reactions were the ones that are better obtained through the reference sources. The 2nd and 4th reactions did not contain any noxious gases, so I assumed those ones were easiest and safest to measure in the laboratory. Hope this helps!

7 0

4 years ago

What is the molality of a solution of 10 g NaOH in 500 g water?<br>Molar mass NaOH = 40 g

umka2103 [35]

Explanation:

Moles of NaOH = 10g / (40g/mol) = 0.25mol.

0.25mol / 500g = 0.50mol / 1000g = 0.50mol/dm³.

The molarity is 0.50mol/dm³.

4 0

3 years ago