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3 years ago

Find the number of moles that are in 2.23 g of Li 2 O and report it with the correct significant figures.

Chemistry

1 answer:

Lesechka [4]3 years ago

8 0

Not sure about the number of significant figures; you can decide where to round, but I would probably say 0.075mol.

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As you read from left to right across the periodic table atomic numbers and what by one of each element

Illusion [34]

Answer:

As we read from left to right across the periodic table atomic numbers are increased by one each of element.

Explanation:

As we move from left to right across the periodic table the atomic number is increased by one and the number of valance electron in an atom increase. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons. This effect lead to the greater nuclear attraction. The electrons are pull towards the nucleus and valance shell get closer to the nucleus. As a result of this greater nuclear attraction atomic radius decreases and ionization energy increases because it is very difficult to remove the electron from atom and more energy is required.

8 0

3 years ago

Consider 2 Al + 6 HCl → 2 AlCl3 + 3 H2 , the reaction of Al with HCl to produce hydrogen gas. What is the pressure of H2 if the

Margaret [11]

Answer : The pressure of hydrogen gas is 8.96 atm.

Explanation :

The given balanced chemical reaction is:

$2Al+6HCl\rightarrow 2AlCl_3+3H_2$

From the balanced chemical reaction we conclude that,

As, 2 moles of Al react to give 3 moles of $H_2$ gas

So, 4.50 moles of Al react to give $\frac{3}{2}\times 4.50=6.75$ moles of $H_2$ gas

Now we have to calculate the moles of $H_2$ gas when percent yield is 75.4.

$\text{The moles of }H_2=75.4\% \times 6.75=\frac{75.4}{100}\times 6.75=5.09moles$

Now we have to calculate the pressure of $H_2$ gas.

Using ideal gas equation :

PV = nRT

where,

P = Pressure of hydrogen gas = ?

V = Volume of the hydrogen gas = 14.0 L

n = number of moles of hydrogen gas = 5.09 moles

R = Gas constant = $0.0821L.atm/mol.K$

T = Temperature of hydrogen gas = 300 K

Putting values in above equation, we get:

$P\times 14.0L=5.09mol\times 0.0821L.atm/mol.K\times 300K\\\\P=8.96atm$

Therefore, the pressure of hydrogen gas is 8.96 atm.

3 0

2 years ago

1. The forks shown are made of silver (Ag). Some of the silver forks

Anon25 [30]

Answer:

Corrosion

Explanation:

Silver, although known as a nobble metal, is also subject to corrosion process such as having silver tarnish when exposed to sulfur and air.

Tarnishing occurs on the surfaces of some metals such as brass, copper, and silver, which results in a corroded layer. Silver tarnish occurs from the chemical reaction that takes place when silver is exposed to sulfur which results in the formation of black Ag₂S

In order to restore the original silver surface, the silver tarnish (silver sulfide) layer is removed.

We have the statement presented here as follows;

The forks shown are made of silver (Ag). Some of the silver forks shown have lost their luster - they have become tarnished. This is an example of <u>Corrosion.</u>

4 0

3 years ago

Which of the following elements does not form a diatomic molecule?

gladu [14]

Answer:

Explanation:

Neon is a noble gas, which is monoatomic.

6 0

3 years ago

Do chemical equations with no reaction still have to be balanced

dangina [55]

Answer:

The same number of atoms of each element must appear on both sides of a chemical equation. However, simply writing down the chemical formulas of reactants and products does not always result in equal numbers of atoms. You have to balance the equation to make the number of atoms equal on each side of an equation.

Explanation:

5 0

3 years ago