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Anna11 [10]
3 years ago
5

For an alloy that consists of 33.5 wt% Pb and 66.5 wt% Sn, what is the composition (a) of Pb (in at%), and (b) of Sn (in at%)? T

he atomic weights for Pb and Sn are 207.2 and 118.7 g/mol, respectively.
Chemistry
1 answer:
Tju [1.3M]3 years ago
5 0

Answer:

Pb: 22.4 at%

Sn: 77.6 at%

Explanation:

It is possible to find at% of Pb and Sn converting mass in moles using molar mass assuming a basis of 100g, thus:

Pb: 33.5g × (1mol / 207.2g) = <em>0.1617mol</em>

Sn: 66.5g × (1mol / 118.7g) = <em>0.5602mol</em>

<em />

Total moles: 0.1617mol + 0.5602mol = 0.7219mol

Composition in at%:

Pb: 0.1617mol / 0.7219mol × 100 = <em>22.4 at%</em>

Sn: 0.5602mol / 0.7219mol × 100 = <em>77.6 at%</em>

<em />

I hope it helps!

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Balance the equation for this reaction:<br> _ FeCl3 + KSCN --<br> --&gt; _ KCI + Fe(SCN)3
kykrilka [37]

Explanation:

FeCl3 + <u>3</u> KSCN ➡ <u>3</u> KCl + Fe(SCN)3

Hope it helps

3 0
3 years ago
Perform the following mathematical operation and express the results to the correct number of significant figures. (0.102 x 0.08
Kobotan [32]

Answer:

<u>2.26 </u>

<u></u>

Explanation:

First you should know what are significant figures,

1 . All non - zero digits are significant.

2 . The zero between two non-  zero are significant.Ex 302 has 3 significant figures.

3. The zero before the decimal and before any non-zero digit is non significant. Example : 0.003 has only 1 significant figure.

4. The zero after non zero are non - significant . But the zeros after the decimal point are significant.

300 has only 1 significant figure

300.0 has 4 significant figure

The least number of significant figures present in the number should be there in the final answer of the calculation.

Look at the number having minimum significant digits :

It is 3 (every number has 3- significant figures ) So the answer should also contain 3 - significant figures.

\frac{0.102\times 0.0821\times 273}{1.01}

First solve the numerator part

\frac{2.285}{1.01}

=2.2635

Round off this number to 3 significant figures.

Answer is =<u> 2.26</u>

It has 3 - significant digit since all the digits are non-zero.

5 0
2 years ago
If Matteo has a model car with a volume of 100 mL and a mass of 200 g, what is the density of their model car?
OLEGan [10]

Answer:

<h2>2 g/mL</h2>

Explanation:

The density of a substance can be found by using the formula

density =  \frac{mass}{volume}  \\

From the question we have

density =  \frac{200}{100}  \\

We have the final answer as

<h3>2 g/mL</h3>

Hope this helps you

6 0
3 years ago
The side chain (R group) of the amino acid serine is CH₂OH. The side chain of the amino acid leucine is CH₂CH(CH₃)₂. Where would
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Answer:

The answer is B, Alanine would be in the interior and serine would be on the exterior of the globular protein.

Explanation:

To further explain, the nature of solubility of side chain determines the position of the amino acid in the globular protein.

The hydrophilic amino acid such as serine are on the outside of the globular protein while the hydrophic amino acids such as leucine and alanine are on the interior of the globular protein.

This is why Alanine would be in the interior and serine would be on the exterior of the globular protein.

Cheers!

4 0
3 years ago
1. If you were working for a beverage company, which molarity would you recommend, and what directions for mixing would you crea
emmasim [6.3K]

Answer: I would prepare a standard solution

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7 0
3 years ago
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