PLEASE HELP URGENT ( photo included)

What is the change in boiling point for a 0.615m solution of Mgl2 in water?

ivanzaharov [21]

Answer : The change in boiling point is, $0.94^oC$

Explanation :

Formula used :

$\Delta T_b=i\times K_f\times m$

where,

$\Delta T_b$ = change in boiling point = ?

i = Van't Hoff factor = 3 (for MgI₂ electrolyte)

$K_f$ = boiling point constant for water = $0.51^oC/m$

m = molality = 0.615 m

Now put all the given values in this formula, we get

$\Delta T_b=3\times (0.51^oC/m)\times 0.615m$

$\Delta T_b=0.94^oC$

Therefore, the change in boiling point is, $0.94^oC$

4 0

3 years ago

What led Thomson to decide that Dalton's atomic model needed to be revised?

jeka94

Answer:

Discovery of electron while studying the properties of cathode ray by Thomson suggested that Dalton atomic model should be revised.

Explanation:

Electron was discovered by j. j. Thomson in 1897 during the study of cathode ray properties.

He constructed the glass tube and create vacuum in it. He applied electric current between electrodes. He noticed that a ray of particles coming from cathode to wards positively charged anode. This ray was cathode ray.

Properties of cathode ray:

The ray is travel in straight line.

The cathode ray is independent of composition of cathode.

When electric field is applied cathode ray is deflected towards the positively charged plate.

Hence it was consist of negatively charged particles.

Symbol= e-

Mass= 9.10938356×10-31 Kg

The electron is subatomic particle that revolve around outside the nucleus and has negligible mass. It has a negative charge.

4 0

3 years ago

A reaction between liquid reactants takes place at −10.0°C in a sealed, evacuated vessel with a measured volume of 45.0L. Measur

maks197457 [2]

Answer: 0.0624 atm

Explanation:-

According to the ideal gas equation:

$PV=nRT$

P = Pressure of the gas = ?

V= Volume of the gas = 45.0 L

T= Temperature of the gas = -10.0°C = 263 K $0^00C=273K$

R= Gas constant = 0.0821 atmL/K mol

n= moles of gas

Moles of gas= $\frac{\text{ given mass}}{\text{ molar mass}}= \frac{19.0g}{146g/mole}=0.130moles$

$P=\frac{nRT}{V}=\frac{0.130\times 0.0821\times 263}{45.0}=0.0624atm$

The pressure of sulfur hexafluoride gas in the reaction vessel after the reaction is 0.0624 atm

3 0

3 years ago

What is not a factor in soil type?

SpyIntel [72]

The answer to this questions is letterB

7 0

3 years ago

A weather balloon is inflated to a volume of 27.9L at a pressure of 732mmHg and a temperature of 30.1?C. The balloon rises in th

masya89 [10]

Answer:

45.4 L

Explanation:

Using Ideal gas equation for same mole of gas as

$\frac {{P_1}\times {V_1}}{T_1}=\frac {{P_2}\times {V_2}}{T_2}$

Given ,

V₁ = 27.9 L

V₂ = ?

P₁ = 732 mmHg

P₂ = 385 mmHg

T₁ = 30.1 ºC

T₂ = -13.6 ºC

The conversion of T( °C) to T(K) is shown below:

T(K) = T( °C) + 273.15

So,

T₁ = (30.1 + 273.15) K = 303.25 K

T₂ = (-13.6 + 273.15) K = 259.55 K

Using above equation as:

$\frac {{P_1}\times {V_1}}{T_1}=\frac {{P_2}\times {V_2}}{T_2}$

$\frac{{732}\times {27.9}}{303.25}=\frac{{385}\times {V_2}}{259.55}$

$\frac{385V_2}{259.55}=\frac{20422.8}{303.25}$

$148225V_2=6729708.26018$

Solving for V₂ , we get:

7 0

4 years ago