Question 1

How much copper is present in a cube that measures 3.20cm on each side, if the density of copper is 8.96 g/mL

Ainat [17]

Answer:

290.32 g

Explanation:

First we calculate the volume of the cube:

Volume = (3.20 cm)³ = 32.768 cm³

Now we convert cubic centimeters to mililiters:

32.768 cm³ * 1 mL / 1 cm³ = 32.768 mL

Finally we calculate the mass, using the equation for density:

Density = mass / Volume

mass = Density * Volume

mass = 8.86 g/mL * 32.768 mL = 290.32 g

7 0

3 years ago

A certain liquid has a normal boiling point of and a boiling point elevation constant . A solution is prepared by dissolving som

jek_recluse [69]

The question is incomplete, the complete question is:

A certain substance X has a normal freezing point of $-6.4^oC$ and a molal freezing point depression constant $K_f=3.96^oC.kg/mol$ . A solution is prepared by dissolving some glycine in 950. g of X. This solution freezes at $-13.6^oC$ . Calculate the mass of urea that was dissolved. Round your answer to 2 significant digits.

Answer: The mass of glycine that can be dissolved is $1.3\times 10^2g$

Explanation:

Depression in the freezing point is defined as the difference between the freezing point of the pure solvent and the freezing point of the solution.

The expression for the calculation of depression in freezing point is:

$\text{Freezing point of pure solvent}-\text{freezing point of solution}=i\times K_f\times m$

OR

$\text{Freezing point of pure solvent}=\text{Freezing point of solution}=i\times K_f\times \frac{m_{solute}\times 1000}{M_{solute}\times w_{solvent}\text{(in g)}}$ ......(1)

where,

Freezing point of pure solvent = $-6.4^oC$

Freezing point of solution = $-13.6^oC$

i = Vant Hoff factor = 1 (for non-electrolytes)

$K_f$ = freezing point depression constant = $3.96^oC/m$

$m_{solute}$ = Given mass of solute (glycine) = ?

$M_{solute}$ = Molar mass of solute (glycine) = 75.07 g/mol

$w_{solvent}$ = Mass of solvent = 950. g

Putting values in equation 1, we get:

$-6.4-(-13.6)=1\times 3.96\times \frac{m_{solute}\times 1000}{75.07\times 950}\\\\m_{solute}=\frac{7.2\times 75.07\times 950}{1\times 3.96\times 1000}\\\\m_{solute}=129.66g=1.3\times 10^2g$

Hence, the mass of glycine that can be dissolved is $1.3\times 10^2g$

5 0

3 years ago

What is the electron configuration for a neutral atom of selenium? For a neutral atom of beryllium?

Anni [7]

Se
1s^2 2s^2 2p^6 3s^2 3p^6 3d^10 4s^2 4p^4
Be
1s^2 2s^2

7 0

4 years ago

Which statement about subatomic particles is true?

trasher [3.6K]

The second option - electrons are the subatomic particles with the smallest mass.

Both protons and electrons have charge (protons are positive and electrons are negative)

Protons and neutrons both equal 1 amu (atomic mass unit), whereas electrons weigh about 1/1000 amu

Electrons orbit around the nucleus, whereas protons and neutrons are inside of the nucleus

And for the last option, I already answered it

8 0

4 years ago

Which of the following liquids is most volatile? Select one: a. cooking oil b. motor oil c. alcohol d. water

LenaWriter [7]

Answer:

Alcohol.

Explanation:

It has the lowest boiling point and high vapour pressure.

7 0

3 years ago