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Gemiola [76]
3 years ago
10

Why are elements in the tall columns of the periodic table called

Chemistry
1 answer:
Natalka [10]3 years ago
5 0
The answer is they follow a patter for valence electrons.
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An "empty" container is not really empty if it contains air. How may moles of nitrogen are in an "empty" two-liter cola bottle a
Lisa [10]

Answer:

1. 0.0637 moles of nitrogen.

2. The partial pressure of oxygen is 0.21 atm.  

Explanation:

1. If we assume ideal behaviour, we can use the Law of ideal gases to find the moles of nitrogen, considering that air composition is mainly nitrogen (78%), oxygen (21%) and argon (1%):  

V_{N_2}=V_{T}\times 0.78=2L \times 0.78 =1.56 L\\PV=nRT\\n_{N_2}=\frac{PV}{RT}=\frac{1 atm\times 1.56 L}{0.0821\frac{atmL}{molK}\times 298 K}\\n_{N_2}= 0.0637 mol

2. Now, in order to find he partial pressure of oxygen we need to find the total moles of air, and then the moles of oxygen. Then, we use these results to determine the molar fraction of oxygen, to multiply it with total pressure and get the partial pressure of oxygen as follows:

n_{total}=\frac{1 atm \times 2L}{0.0821 \frac{atmL}{molK}298K}=0.0817 mol

V_{O_2}=2L \times 0.21 = 0.42 L\\n_{O_2}=\frac {1atm \times 0.42 L}{0.0821 \frac{atm L}{mol K}298 K}=0.0172 mol\\X_{O_2}=\frac{n_{O_2}}{n_{total}}=\frac{0.0172 mol}{0.0817 mol}= 0.21

P_{O_2}=X_{O_2} \times P = 1 atm \times 0.21 = 0.21 atm

As you see, the molar fraction and volume fraction are the same because of the assumption of ideal behaviour.  

3 0
2 years ago
Why do electrons gain energy?
Novay_Z [31]

Electrons can gain the energy it needs by absorbing light. If the electron jumps from the second energy level down to the first energy level, it must give off some energy by emitting light. The atom absorbs or emits light in discrete packets called photons, and each photon has a definite energy.

8 0
3 years ago
Read 2 more answers
Fluoride is moderately basic, by far the most basic of the halides. It is a terrible leaving group. Fluoride is many orders of m
TEA [102]

Answer:   Bromide is many orders of magnitude better than fluoride in leaving group ability

Explanation:

As Size of an atom  Increases,  the Basicity Decreases this is because  if we move downwards  from the top of the periodic table to the bottom of the periodic table, the size of an atom increases. As size increases, basicity will decrease, meaning the element  will be less likely to act as a base implying that the element will be less likely to share its electrons.

in the same vein. With an increase in size, basicity decreases, making the ability of the leaving group to leave increase to increase . This can be seen in the halogens going down the group  from

F--- worst

Cl----fair

Br ----good

 I-----excellent

with fluorine having the worst ability to leave than Bromine which is better in terms of the leaving group ability.

3 0
3 years ago
Which of these common substances is a mixture?
ivolga24 [154]
B .pure water it’s made up of oxygen and hydrogen “H2O”
5 0
3 years ago
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Which of the following are advantages of the SI system?
lions [1.4K]
The correct answer is A, B and C
3 0
3 years ago
Read 2 more answers
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