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4 years ago

Explain why a solution has a lower boiling point than the pure solvent

1 answer:

7 0

Because the intention is to boil the solution, the purpose of the solvent is to dissolve so it has a higher boiling point so ensure it stays in liquid form and doesn't evaporate into a gas

also, a pure solvent is made of 1 substance so it has 1 boiling point and the solution must evaporate/boil first

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A strong acid _____. has a large K a has a large concentration of hydroxide ions has a small K a has a high pH number

In-s [12.5K]

Answer:

H2SO4

Explanation:

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3 years ago

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1.What is another term for the 24 hour clock?

s344n2d4d5 [400]

Answer:

military time

Explanation:

military time

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3 years ago

Do centromeres divide at anaphase i or ii

ddd [48]

Anaphase 1 is when centromeres divide

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3 years ago

An aqueous solution is listed as being 33.8% solute by mass with a density of 1.15 g/mL, the molar mass of the solute is 145.6 g

vodomira [7]

Answer:

A) 2.69 M

B) 0.059

Explanation:

A) We have:

33.8% solute by mass= 33.8 g solute/100 g solution

molarity = mol solute/ 1 L solution

molarity= $\frac{33.8 g solute}{100 g solution}$ x $\frac{1.15 g solution}{1 ml}$ x $\frac{1 mol solute}{145.6 g solute}$ x $\frac{1000 ml}{1 L}$

molarity= 2.69 mol solute/L solution = 2.69 M

B) We know that there are 33.8 g of solute in 100 g of solution.

As the total solution is compounded by solute+solvent (in this case, solvent is water), the mass of water is the difference between the mass of the total solution and the mass of solute:

mass of water= 100 g - 33.8 g = 66.2 g

Now, we calculate the number of mol of both solute and water:

mol solute= 33.8 g solute x $\frac{1 mol solute}{145.6 g}$ = 0.232 mol

mol H20= 66.2 g H₂O x $\frac{1 mol H2O}{18 g}$

Finally, the mol fraction of solute (Xsolute) is calculated as follows:

Xsolute= $\frac{mol solute}{total mol}= \frac{mol solute}{mol solute + mol H2O}=\frac{0.232 mol}{0.232 mol + 3.677 mol}$

Xsolute= 0.059

4 0

3 years ago

When electromagnetic radiation of wavelength 300nm falls on the surface of sodium electrons are emitted with a KE of 1.68 * 10 5

gtnhenbr [62]

Answer:

3.83 × 10⁻¹⁹ J; 518 nm

Step-by-step explanation:

The equation for the photoelectric effect is

hf = Φ + KE

Data:

λ = 300 nm = 300 × 10⁻⁹ m

KE = 1.68 × 10⁵ J/mol

Calculations:

Part 1. Minimum energy to remove an electron

(a) Calculate the energy of the photon

fλ = c

f = c/λ Divide each side by λ

E = hf

E = hc/λ

E = (6.626× 10⁻³⁴ × 2.998 × 10⁸)/(300 × 10⁻⁹)

E = 6.622 × 10⁻¹⁹ J

(b) Calculate the KE of one electron

KE = 1.68 × 10⁵ × 1/(6.022 × 10²³)

KE = 2.790 × 10⁻¹⁹ J

(c) Calculate the work function

hf = Φ + KE Subtract KE from each side

Φ = 6.622 × 10⁻¹⁹ - 2.790 × 10⁻¹⁹

Φ = 3.83 × 10⁻¹⁹ J

The minimum energy to remove an electron from a sodium atom

is 3.83 × 10⁻¹⁹ J.

Part 2. Maximum wavelength to remove an electron

The photon must have just enough energy to overcome the work function and leave the electron with zero kinetic energy.

E = Φ

hc/λ = Φ Multiply each side by λ

hc = Φ λ Divide each side by Φ

λ = hc/ Φ

λ = (6.626 × 10⁻³⁴ × 2.998 × 10⁸)/(3.83 × 10⁻¹⁹)

λ = 5.18 × 10⁻⁷ m Convert to nanometres

λ = 518 nm

The maximum wavelength that will cause an electron to move is 518 nm.

6 0

3 years ago

Read 2 more answers