Which of the following statements are true?

How many moles of nitroge are there in 50.0 g of nitrogen?

chubhunter [2.5K]

1.785714286 moles

The number of moles (n) for nitrogen is: [ n=50.0÷28.0 ] = 1.785714286 moles.

8 0

3 years ago

An unknown compound has the following chemical formula:

Softa [21]

Answer:

Formula of the compound = $P_2O_5$

Explanation:

Given,

No. of mole of O = 8.20 mol

No. of mole of P = 3.30 mol

Chemical formula = $P_2O_x$

Ratio of P and O = $\frac{2}{x}$

$\frac{2}{x} =\frac{3.3}{8.20} \\x \times 3.3 = 8.20 \times 2\\x = \frac{8.20 \times 2}{3.3} \\x=4.9969\\ = 5$

formula of the compound = $P_2O_5$

5 0

3 years ago

Convert 213.62 grams of xenon gas at STP to L.

jolli1 [7]

Answer: The coefficient is 3.645

The exponent is 1

There are 4 significant digits

The rightmost significant figure is 5

Explanation:

Scientific notation is defined as the representation of expressing the numbers that are too big or too small and are represented in the decimal form with one digit before the decimal point times 10 raise to the power.

For example : 5000 is written as $5.0\times 10^3$

According to avogadro's law, 1 mole of every gas contains avogadro's number $6.023\times 10^{23}$ of particles, occupy 22.4 L at STP and weighs equal to its molecular mass.

131.29 g of Xe occupy = 22.4 L at STP.

Thus 213.62 g of $Xe$ occupy = $\frac{22.4}{131.29}\times 213.62=36.45L$ at STP.

Scientific notation = $3.645\times 10^1L$

The coefficient is 3.645

The exponent is 1

There are 4 significant digits

The rightmost significant figure is 5

4 0

3 years ago

1. How does protein substance in animal hide or skin be preserved from bacterial infection during tanning?

anyanavicka [17]

Answer:

1. By being cured

2. To remove the silica impurities from haemetite

3. The cathode will be bronze while the anode will be the silver

4. i) Wastes from industrial processes

ii) Waste waters and sewage

iii) Dumping of wastes into water bodies

5) Three methods to reduce air pollution includes

i) Promote the use of recycled of materials

ii) Promote and use renewable sources of energy

iii) Limit activities that involve the burning of fuels such as encouraging the use of mass transit buses, preventing the occurrence of fires in forests

Explanation:

1. In order to preserve the proteins in the hides of animal skin from putrefaction they are cured with salt to remove by, osmotic pressure difference, the water content present in the animal hide

2. To remove the silica impurities from haemetite

The calcium oxide obtained from the decomposition of calcium carbonate undergoes a chemical reaction with the sand impurities in the mineral, haematite, to form calcium silicate or s l a g

3. Electroplating involves charging the metal to be electroplated negatively that is making it the cathode and placing it in an electrolytic cell that has a solution of the metal ions containing the metal salts

Therefore, the bronze medal to be plated with silver will be made the cathode while the silver from which we obtain the silver ions will be made the anode

4. Three causes of water pollution includes

Wastes from industrial processes

Waste waters and sewage

Dumping of wastes into water bodies

5. The major causes of air pollution are the oxides produced from the combustion of fossil fuels such as sulfur dioxide, carbon dioxide, carbon monoxide as well as chemical gases from industrial processes.

8 0

3 years ago

A sample of gas has a pressure of 742 torr. What is the pressure in atmospheres?

ycow [4]

Answer:742 torr= approximately 0.976 atm

Explanation:

Since we know that one atm= 760 torr, we can compute the following calculation:

(742 torr/1)*(1atm/760torr)=0.976316 atm

Remember sig figs (3) to round it to 0.976 atm

$\frac{742 torr}{1}$ * $\frac{1 atm}{760 torr}$ =0.976316=0.976 atm

(torr cancels out and we're left with atm)

Hope this helps :)

8 0

3 years ago