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3 years ago

How many Al atoms are there in 40.5 g of Al foil? Al:27

Chemistry

1 answer:

andrew-mc [135]3 years ago

4 0

Answer:

c) 9.03 x 10^23

Explanation:

find the molar mass of Al

Al is 27.0 grams

Then use that, to find the number of moles in Aluminum.

Then use Avogadro's number which is 6.02 * 10^23

After that, write all of that down with dimensional analysis.

40.5 g * 1 mol/ 27.0 g of Al * 6.02 x 10^23 / 1mol

As your final answer, you will get 9.03 * 10^23 atoms with sig figs.

Hope it helped!

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Pls help me in this:(

antiseptic1488 [7]

Answer:

a) 26.98

b) 3

c) 3* 1.01 = 3.03

d) 3 *16 = 48

e) 26.98 + 3.03 + 48 = 78.01

f) 6.023 * 10²³

3 0

3 years ago

How many moles are 21.67 L of NH4CI?<br> Type your answer...

NNADVOKAT [17]

Answer:

0.967mole

Explanation:

Given parameters:

Volume of NH₄Cl = 21.67L

Unknown:

Number of moles = ?

Solution:

We assume that the volume was taken at standard temperature and pressure,

Then;

Number of moles = $\frac{volume }{22.4L}$

Number of moles = $\frac{21.67}{22.4}$ = 0.967mole

6 0

3 years ago

Ideal gas (n 2.388 moles) is heated at constant volume from T1 299.5 K to final temperature T2 369.5 K. Calculate the work and h

bija089 [108]

Answer : The work, heat during the process and the change of entropy of the gas are, 0 J, 3333.003 J and -10 J respectively.

Explanation :

(a) At constant volume condition the entropy change of the gas is:

$\Delta S=-n\times C_v\ln \frac{T_2}{T_1}$

We know that,

The relation between the $C_p\text{ and }C_v$ for an ideal gas are :

$C_p-C_v=R$

As we are given :

$C_p=28.253J/K.mole$

$28.253J/K.mole-C_v=8.314J/K.mole$

$C_v=19.939J/K.mole$

Now we have to calculate the entropy change of the gas.

$\Delta S=-n\times C_v\ln \frac{T_2}{T_1}$

$\Delta S=-2.388\times 19.939J/K.mole\ln \frac{369.5K}{299.5K}=-10J$

(b) As we know that, the work done for isochoric (constant volume) is equal to zero. $(w=-pdV)$

(C) Heat during the process will be,

$q=n\times C_v\times (T_2-T_1)=2.388mole\times 19.939J/K.mole\times (369.5-299.5)K= 3333.003J$

Therefore, the work, heat during the process and the change of entropy of the gas are, 0 J, 3333.003 J and -10 J respectively.

7 0

3 years ago

The effectiveness of a chemical sanitizer can be limited by

Serjik [45]

Chemical sanitizer effectiveness, decreases with increase in pH . And most soap and detergent are alkaline in nature, that limits its effectiveness. So they should be rinsed off completely for proper effectiveness of santizer. So improper rinsing limits the effectiveness of a sanitizer.

So , the answer is improper rinsing after that still a detergent residue remains limits the effectiveness of sanitizer.

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3 years ago

'Synthetic detergents are better than soaps'. Justify this statement

Shtirlitz [24]

Answer:

Synthetic detergents can be used for washing purposes even when the water is hard, whereas soaps are not suitable for washing with hard water. This is because of the fact that synthetic detergents can lather with hard water. Hence, Synthetic detergents better than soaps.

3 0

3 years ago

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