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3 years ago

What is density? chemistry

Chemistry

1 answer:

yawa3891 [41]3 years ago

6 0

Answer: Density means the compactness of an object

I hope this helps, and Happy Holidays! :)

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The critical role of the atmosphere is best described as ?

olchik [2.2K]

Answer:

I would say to keep the oxygen we breathe in or to filter out the bed uv rays from the sun like radiation.

Explanation:

im guessing

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3 years ago

How many li are in 2.5 moles of li

NARA [144]

Answer:

15.06 × 10²³ atoms of Li

Explanation:

Given data:

Number of moles of Li = 2.5 mol

Number of toms of Li = ?

Solution:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

For example,

18 g of water = 1 mole = 6.022 × 10²³ molecules of water

1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen

For 2.5 mol of Li:

1 mole of lithium = 6.022 × 10²³ atoms of Li

2.5 mol × 6.022 × 10²³ atoms of Li / 1 mol

15.06 × 10²³ atoms of Li

8 0

4 years ago

How many covalent bonds can Carbon, Hydrogen, Nitrogen, Or Oxygen form?

Sergio [31]

Carbon can form four covalent bonds.
Hydrogen can form one covalent bond.
Nitrogen can form three covalent bonds.
Oxygen can form two covalent bonds.

4 0

4 years ago

Calculate the number of grams of sodium chloride in the solution. (Hint: Remember that sodium chloride is a strong electrolyte.)

creativ13 [48]

The question is incomplete, here is the complete question:

A solution contains 0.115 mol $H_2O$ and an unknown number of moles of sodium chloride. The vapor pressure of the solution at 30°C is 25.7 torr. The vapor pressure of pure water at this temperature is 31.8 torr. Calculate the number of grams of sodium chloride in the solution. (Hint: Remember that sodium chloride is a strong electrolyte.)

Answer: The mass of sodium chloride in the solution is 0.714 grams

Explanation:

The formula for relative lowering of vapor pressure will be:

$\frac{p^o-p_s}{p^o}=i\times \chi_{\text{solute}}$

where,

$p^o$ = vapor pressure of solvent (water) = 31.8 torr

$p^s$ = vapor pressure of the solution = 25.7 torr

i = Van't Hoff factor = 2

$\chi_{\text{solute}}$ = mole fraction of solute (sodium chloride) = ?

Putting values in above equation, we get:

$\frac{31.8-25.7}{31.8}=2\times \chi_{NaCl}\\\\\chi_{NaCl}=0.0959$

Mole fraction of a substance is calculated by using the equation:

$\chi_A=\frac{n_A}{n_A+n_B}$

$\chi_{\text{NaCl}}=\frac{n_{\text{NaCl}}}{n_{\text{NaCl}}+n_{\text{water}}}$

We are given:

Moles of water = 0.115 moles

$0.0959=\frac{n_{\text{NaCl}}}{n_{\text{NaCl}}+0.115}\\\\n_{\text{NaCl}}=0.0122mol$

To calculate the mass for given number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Moles of NaCl = 0.0122 moles

Molar mass of NaCl = 58.5 g/mol

Putting values in above equation, we get:

$0.0122mol=\frac{\text{Mass of NaCl}}{58.5g/mol}\\\\\text{Mass of NaCl}(0.0122mol\times 58.5g/mol)=0.714g$

Hence, the mass of sodium chloride in the solution is 0.714 grams

5 0

4 years ago

What makes the human thumb so special?

Sophie [7]

Answer:

The thumb alone is controlled by nine separate muscles; The hand has been used as a symbol of protection since ancient times; The human hand is different to the hands or paws of other animals, because it has fingers and a thumb that can work together. Each finger has 3 bones and the thumb has two bones

Explanation:

3 0

3 years ago

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What is density? chemistry​

What is density? chemistry