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adelina 88 [10]
2 years ago
15

Which of the following is a pure substance?

Chemistry
1 answer:
Mazyrski [523]2 years ago
8 0

Answer:

1. B

2. 100 C

3.  C

4. D

5. D

Explanation:

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Calculate the empirical formula for a compound containing 67.6% Hg 10.8% S 21.6% O
pashok25 [27]

Answer:

HgSO₄

Explanation:

% => g => moles => ratio => reduce => empirical ratio

%Hg = 67.6% => 67.6g/201g/mol = 0.34mol

%S    = 10.8% => 10.8g/32g/mol = 0.34mol

%O   = 21.6% => 21.6g/16g/mol = 1.35mol

Hg:S:O => 0.34:0.34:1.35

Reduce to whole number ratio by dividing by the smaller mole value...

Hg:S:O => 0.34/.34:0.34/.34:1.35/.34 => Empirical Ratio = 1:1:4

∴ Empirical Formula is HgSO₄

3 0
3 years ago
Which of the following processes does our Sun and other stars in our galaxy use to create energy?
Usimov [2.4K]

Answer:

fusion reaction

The simple answer is that the sun, like all stars, is able to create energy because it is essentially a massive fusion reaction. Scientists believe that this began when a huge cloud of gas and particles (i.e. a nebula) collapsed under the force of its own gravity – which is known as Nebula Theory.

Explanation:

hope this helps

5 0
3 years ago
The radioactive substance cesium-137 has a half-life of 30 years. The amount At (in grams) of a sample of cesium-137 remaining a
stealth61 [152]

<u>Answer:</u> The amount of sample left after 20 years is 288.522 g and after 50 years is 144.26 g

<u>Explanation:</u>

We are given a function that calculates the amount of sample remaining after 't' years, which is:

A_t(t)=458\times (\frac{1}{2})^{\frac{t}{30}

  • <u>For t = 20 years</u>

Putting values in above equation:

A_t(t)=458\times (\frac{1}{2})^{\frac{20}{30}

A_t(t)=288.522g

Hence, the amount of sample left after 20 years is 288.522 g

  • <u>For t = 50 years</u>

Putting values in above equation:

A_t(t)=458\times (\frac{1}{2})^{\frac{50}{30}

A_t(t)=144.26g

Hence, the amount of sample left after 50 years is 144.26 g

6 0
3 years ago
Which of the data sets qualitative data?
Kaylis [27]

Answer:

Uh, the second one?

Explanation:

Try to restate the question please.

3 0
3 years ago
Read 2 more answers
A solution of hydrocloric acid has a molarity of 2.25 M HCl. If a reaction requires 5.80 g of HCI, what
Natali [406]

Answer:

0.071L

Explanation:

From the question given, we obtained the following data:

Molarity of HCl = 2.25 M

Mass of HCl = 5.80g

Molar Mass of HCl = 36.45g/mol

Number of mole of HCl =?

Number of mole = Mass /Molar Mass

Number of mole of HCl = 5.8/36.45 = 0.159mole

Now, we can obtain the volume required as follows:

Molarity = mole /Volume

Volume = mole /Molarity

Volume = 0.159mole/ 2.25

Volume = 0.071L

4 0
3 years ago
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