Which of the following methods correctly describes the preparation of 1.00 L of an aqueous solution of 0.500 M NaOH?

Find the pH of a 0.0015 M HCl solution

kolbaska11 [484]

Answer:

I got 1.82

Explanation:

Explanation: pH is given by the equation,. pH=−log[H+]. [H+] is the hydrogen ion concentration in terms of morality.

4 0

3 years ago

A certain liquid has a normal freezing point of and a freezing point depression constant . Calculate the freezing point of a sol

katrin2010 [14]

The question is incomplete, the complete question is:

A certain liquid X has a normal freezing point of $0.80^oC$ and a freezing point depression constant $K_f=7.82^oC.kg/mol$ . Calculate the freezing point of a solution made of 81.1 g of iron(III) chloride () dissolved in 850. g of X. Round your answer to significant digits.

<u>Answer:</u> The freezing point of the solution is $-17.6^oC$

<u>Explanation:</u>

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 = $0.80^oC$

Freezing point of solution = $?^oC$

i = Vant Hoff factor = 4 (for iron (III) chloride as 4 ions are produced in the reaction)

$K_f$ = freezing point depression constant = $7.82^oC/m$

$m_{solute}$ = Given mass of solute (iron (III) chloride) = 81.1 g

$M_{solute}$ = Molar mass of solute (iron (III) chloride) = 162.2 g/mol

$w_{solvent}$ = Mass of solvent (X) = 850. g

Putting values in equation 1, we get:

$0.8-(\text{Freezing point of solution})=4\times 7.82\times \frac{81.1\times 1000}{162.2\times 850}\\\\\text{Freezing point of solution}=[0.8-18.4]^oC\\\\\text{Freezing point of solution}=-17.6^oC$

Hence, the freezing point of the solution is $-17.6^oC$

6 0

2 years ago

- 5. Describe the general trend in atomic radil across a row of the periodic table.

sattari [20]

Answer:

Across a row, atomic radii decreases.

Explanation:

It decreases because nuclear charge increases across a row, electrons are added to the same shell and shielding remains constant. Therefore the outer electrons are more attracted to the nucleus making the atom smaller.

8 0

2 years ago

A 2.0 L container of nitrogen gas had a pressure of 3.2 atm. What volume would be necessary to decrease the pressure to 1.0 atm

beks73 [17]

Answer:

6.4 L

Explanation:

When all other variables are held constant, you can use Boyle's Law to find the missing volume:

P₁V₁ = P₂V₂

In this equation, "P₁" and "V₁" represent the initial pressure and volume. "P₂" and "V₂" represent the final pressure and volume. You can find the theoretical volume by plugging the given values into the equation and simplifying.

P₁ = 3.2 atm P₂ = 1.0 atm

V₁ = 2.0 L V₂ = ? L

P₁V₁ = P₂V₂ <----- Boyle's Law

(3.2 atm)(2.0 L) = (1.0 atm)V₂ <----- Insert values

6.4 = (1.0 atm)V₂ <----- Simplify left side

6.4 = V₂ <----- Divide both sides by 1.0

6 0

2 years ago

Which is a problem associated with the use of trees for biomass? I. Potential deforestation II. Burning fossil carbon III. Poten

BigorU [14]

Answer:

Both Option (I) and Option (III)

Explanation:

Biomass is usually defined as those organic molecules that are obtained from plants and animals, in order to produce energy. It is a renewable resource. Some of the examples of biomass include wood, crop, animal fossil fuel.

A large number of trees are being cut down to construct these biomass energies such as woods. This results in the deforestation process where the forested areas are converted into empty dry soils. This results in the increasing rate of erosion because the prevailing wind and flowing water can easily carry away the topsoil and loses the fertility of the soil.

Thus, the correct answers are both options (I) and (III).

7 0

3 years ago