Atomic mass silicon = 28.085 u
1 mol Si ---------------- 28.085 g
? ------------------------ 245 g
245 x 1 / 28.085 => 8.72 mol
answer A
Answer:
Measuring distances to stars through stellar parallax. Measuring distances to stars through the moving cluster method. Astronomers measure the temperature of a star by looking at the star's color and its spectrum. The apparent brightness of a star tells how bright it seems to us
Explanation:
Answer:
I don't see a specific question, so I'll make a few comments and hope that answers the reason for the post.
Explanation:
Zinc(Zn) does react with iron chloride, since zinc is a more reactive metal than the iron.
When Zn is introduced to an iron (III) chloride solution, the Zn disoplaces the Fe atom in a displacement reaction.
The chemical equation of the reaction:
Zn + Fe(III)Cl3 → ZnCl3 + Fe
Energy is often realeased in this type of reaction, since the resulting chemical products have a lower energy that the reactants.
There are several metals more reactive than iron. One of the more interesting examples of a highly exothermic reaction with iron chloride (rust) is the reaction of aluminum with iron chloride. `This is highly exothermic and is labelled a thermite reaction. It provides a spectacular flame that is not enough to weld railroad tracks together.
Answer:
Explanation:
Your strategy here will be to
use the chemical formula of carbon dioxide to find the number of molecules of
CO
2
that would contain that many atoms of oxygen
use Avogadro's constant to convert the number of molecules to moles of carbon dioxide
use the molar mass of carbon dioxide to convert the moles to grams
So, you know that one molecule of carbon dioxide contains
one atom of carbon,
1
×
C
two atoms of oxygen,
2
×
O
This means that the given number of atoms of oxygen would correspond to
4.8
⋅
10
22
atoms O
⋅
1 molecule CO
2
2
atoms O
=
2.4
⋅
10
22
molecules CO
2
Now, one mole of any molecular substance contains exactly
6.022
⋅
10
22
molecules of that substance -- this is known as Avogadro's constant.
In your case, the sample of carbon dioxide molecules contains
2.4
⋅
10
22
molecules CO
2
⋅
1 mole CO
2
6.022
⋅
10
23
molecules CO
2
=
0.03985 moles CO
2
Finally, carbon dioxide has a molar mass of
44.01 g mol
−
1
, which means that your sample will have a mass of
0.03985
moles CO
2
⋅
44.01 g
1
mole CO
2
=
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
∣
∣
a
a
1.8 g
a
a
∣
∣
−−−−−−−−−
The answer is rounded to two sig figs, the number of sig figs you have for the number of atoms of oxygen present in the sample.
<u>Answer:</u> The value of equilibrium constant for the given reaction is 56.61
<u>Explanation:</u>
We are given:
Initial moles of iodine gas = 0.100 moles
Initial moles of hydrogen gas = 0.100 moles
Volume of container = 1.00 L
Molarity of the solution is calculated by the equation:
Equilibrium concentration of iodine gas = 0.0210 M
The chemical equation for the reaction of iodine gas and hydrogen gas follows:
<u>Initial:</u> 0.1 0.1
<u>At eqllm:</u> 0.1-x 0.1-x 2x
Evaluating the value of 'x'
The expression of 
for above equation follows:
![K_c=\frac{[HI]^2}{[H_2][I_2]}](https://tex.z-dn.net/?f=K_c%3D%5Cfrac%7B%5BHI%5D%5E2%7D%7B%5BH_2%5D%5BI_2%5D%7D)
![[HI]_{eq}=2x=(2\times 0.079)=0.158M](https://tex.z-dn.net/?f=%5BHI%5D_%7Beq%7D%3D2x%3D%282%5Ctimes%200.079%29%3D0.158M)
![[H_2]_{eq}=(0.1-x)=(0.1-0.079)=0.0210M](https://tex.z-dn.net/?f=%5BH_2%5D_%7Beq%7D%3D%280.1-x%29%3D%280.1-0.079%29%3D0.0210M)
![[I_2]_{eq}=0.0210M](https://tex.z-dn.net/?f=%5BI_2%5D_%7Beq%7D%3D0.0210M)
Putting values in above expression, we get:
Hence, the value of equilibrium constant for the given reaction is 56.61
