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sleet_krkn [62]
3 years ago
14

In 4/2HE, what does the number 4 indicate?

Chemistry
1 answer:
11Alexandr11 [23.1K]3 years ago
6 0

The number 4 in the 4/2He indicates the atomic mass number of helium.

Answer: Option 3

<u>Explanation: </u>

The elements present in periodic table generally represented as X_{Z}^{A}. Here X will be the element in the periodic table, A is the atomic mass number of the element X and Z is the atomic number of the element X.

So, the number 4 is the atomic mass number of He and He-4 is the stable isotope of helium which can also be termed as alpha particle.

               Mass number = number of protons + neutrons count.

Thus the number 4 denotes the Helium's atomic mass number.

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A 100 g sample of potassium chlorate, KCIO3(s), is completely decomposed by heating:
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Explanation:
In order to be able to calculate the volume of oxygen gas produced by this reaction, you need to know the conditions for pressure and temperature.
Since no mention of those conditions was made, I'll assume that the reaction takes place at STP, Standard Temperature and Pressure.
STP conditions are defined as a pressure of
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and a temperature of
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∘
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- this is known as the molar volume of a gas at STP.
So, in order to find the volume of oxygen gas at STP, you need to know how many moles of oxygen are produced by this reaction.
The balanced chemical equation for this decomposition reaction looks like this
2
KClO
3(s]
heat
×
−−−→
2
KCl
(s]
+
3
O
2(g]
↑
⏐
⏐
Notice that you have a
2
:
3
mole ratio between potassium chlorate and oxygen gas.
This tells you that the reaction will always produce
3
2
times more moles of oxygen gas than the number of moles of potassium chlorate that underwent decomposition.
Use potassium chlorate's molar mass to determine how many moles you have in that
231-g
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231
g
⋅
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3
122.55
g
=
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3
Use the aforementioned mole ratio to determine how many moles of oxygen would be produced from this many moles of potassium chlorate
1.885
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3
⋅
3
moles O
2
2
moles KClO
3
=
2.8275 moles O
2
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2.8275
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6 0
3 years ago
Classify the below solids as amorphous or crystalline. emerald glass MgCl, rubber​
svet-max [94.6K]

Answer:

Here yo

Explanation:

6 0
2 years ago
Read 2 more answers
A large weather balloon filled with helium has a volume of 7.00 x 102 L at STP. Which expression should be used to find the mass
balandron [24]

Answer:

mass of Helium = mole of Helium x Molarmass of Helium

Explanation:

Mole of Helium = volume of Helium/ 22.4dm^3/mol

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7 0
3 years ago
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