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3 years ago

4. Does an atom of an element always have the same number of neutrons as other atoms of the same

Chemistry

1 answer:

Sergeeva-Olga [200]3 years ago

6 0

Explanation:

No. Isotopes are atoms of the same element with different atomic masses (due to the different number of neutrons)

For example, carbon exists as carbon-12 and carbon-14, which both have 6 protons but have 6 and 8 neutrons respectively.

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Aluminum reacts with sulfur gas to produce aluminum sulfide. a) What is the limiting reactant? What is the excess reagent? b) Ho

Sophie [7]

Answer:

a) Limiting: sulfur. Excess: aluminium.

b) 1.56g Al₂S₃.

c) 0.72g Al

Explanation:

Hello,

In this case, the initial mass of both aluminium and sulfur are missing, therefore, one could assume they are 1.00 g for each one. Thus, by considering the undergoing chemical reaction turns out:

$2Al(s)+3S_2(g)\rightarrow 2Al_2S_3(s)\\$

a) Thus, considering the assumed mass (which could be changed based on the one you are given), the limiting reagent is identified as shown below:

$n_S^{available}=1.00gS_2*\frac{1molS_2}{64gS_2} =0.0156molS_2\\n_S^{consumed\ by \ Al}=1.00gAl*\frac{1molAl}{27gAl}*\frac{3molS_2}{2molAl}=0.0556molS_2$

Thereby, since there 1.00g of aluminium will consume 0.0554 mol of sulfur but there are just 0.0156 mol available, the limiting reagent is sulfur and the excess reagent is aluminium.

b) By stoichiometry, the produced grams of aluminium sulfide are:

$m_{Al_2S_3}=0.0156molS_2*\frac{2molAl_2S_3}{3molS_2} *\frac{150gAl_2S_3}{1molAl_2S_3} =1.56gAl_2S_3$

c) The leftover is computed as follows:

$m_{Al}^{excess}=(0.0556-0.0156)molS_2*\frac{2molAl}{3molS_2}*\frac{27gAl}{1molAl} =0.72 gAl\\$

NOTE: Remember I assumed the quantities, they could change based on those you are given, so the results might be different, but the procedure is quite the same.

Best regards.

7 0

3 years ago

Atomic number and mass of O

lesya692 [45]

Atomic number is 8 and atomic mass is taken as 16 amu

3 0

3 years ago

Read 2 more answers

A full bottle of water was left outside overnight in freezing temperatures, causing the bottle to crack. No mass was added or re

kodGreya [7K]

Answer:The correct answer is option C.

Explanation;

Water has unique property that is, it expands on freezing.Which is the reason for less density of ice than water. The cracking of the bottle was due to the expansion of water (present inside the bottle) on freezing.

Generally, density is inversely proportional to the volume of the substance.

$Density=\frac{Mass}{Volume}$

$Density\propto \frac{1}{Volume}$

As we know ,that water expands on freezing which means that volume increases. And with increase in volume of density decreases.

Hence, the correct answer is option C.

6 0

3 years ago

PLEASE HELP ME!!!

irina [24]

that's the answer I think

6 0

2 years ago

Read 2 more answers

What are the functions of ammonia in the solvay process

enot [183]

The ammonia gas is absorbed in the concentrated brine to produce aqueous sodium chloride and aqueous ammonia. This ammoniation process is exothermic, so energy is released as heat. The ammonia tower eventually needs to be cooled.

7 0

3 years ago