Which statement is true for both electromagnetic waves and mechanical

In a laboratory experiment, students synthesized a new compound and found that when 7.229 grams of the compound were dissolved i

STALIN [3.7K]

The question is incomplete, here is the complete question:

The common laboratory solvent chloroform is often used to purify substances dissolved in it. The vapor pressure of chloroform, CHCl₃, is 173.11 mm Hg at 25°C.

In a laboratory experiment, students synthesized a new compound and found that when 7.229 grams of the compound were dissolved in 207.8 grams of chloroform, the vapor pressure of the solution was 170.51 mm Hg. The compound was also found to be nonvolatile and a non-electrolyte. What is the molecular weight of this compound?

<u>Answer:</u> The molecular mass of the compound is 481.9 g/mol

<u>Explanation:</u>

The equation used to calculate relative lowering of vapor pressure follows:

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

where,

$\frac{p^o-p_s}{p^o}$ = relative lowering in vapor pressure

i = Van't Hoff factor = 1 (for non electrolytes)

$\chi_{solute}$ = mole fraction of solute = ?

$p^o$ = vapor pressure of pure chloroform = 173.11 mmHg

$p_s$ = vapor pressure of solution = 170.51 mmHg

Putting values in above equation, we get:

$\frac{173.11-170.51}{173.11}=1\times \chi_A\\\\\chi_A=0.0150$

This means that 0.0150 moles of compound is present in the solution

To calculate the number of moles, we use the equation:

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

Moles of compound = 0.0150 moles

Given mass of compound = 7.229 g

Putting values in above equation, we get:

$0.0150mol=\frac{7.229g}{\text{Molar mass of compound}}\\\\\text{Molar mass of compound}=\frac{7.229g}{0.0150mol}=481.9g/mol$

Hence, the molecular mass of the compound is 481.9 g/mol

5 0

3 years ago

A 1.555-g sample of baking soda decomposes with heat to produce 0.991 g Na2CO3. Refer to Example Exercise 14.l and show the calc

Sunny_sXe [5.5K]

Answer:

a) 101%

b)59.7%

Explanation:

The equation for the thermal decomposition of baking soda is shown;

2NaHCO3 → Na2CO3 + H2O + CO2

Number of moles of baking soda= mass/molar mass= 1.555g/84.007 g/mol = 0.0185 moles

From the reaction equation;

2 moles of baking soda yields 1 mole of sodium carbonate

0.0185 moles of baking soda will yield = 0.0185 moles ×1 /2 = 9.25 ×10^-3 moles of sodium carbonate.

Therefore, mass of sodium carbonate= 9.25 ×10^-3 moles × 106gmol-1= 0.9805 g of sodium carbonate. This is the theoretical yield of sodium carbonate.

%yield = actual yield/theoretical yield ×100

% yield = 0.991/0.9805 ×100

%yield = 101%

Since ;

2NaHCO3 → Na2CO3 + H2O + CO2

And H2O + CO2 ---> H2CO3

Hence I can write, 2NaHCO3 → Na2CO3 + H2CO3

Molar mass of H2CO3= 62.03 gmol-1

Molar mass of baking soda= 84 gmol-1

Therefore, mass of baking soda=

0.325/62.03 × 2 × 84 = 0.88 g of NaHCO3

% of NaHCO3= 0.88/1.473 × 100 = 59.7%

7 0

3 years ago

What particle decay is this? 210 83 Bi→210 84 Po

sesenic [268]

Answer:

Beta emission

Explanation:

In beta emission, a neutron is converted into a proton thereby emitting an electron and a neutrino. A neutrino is a particle that serves to balance the spins.

When a nucleus undergoes beta emission, the mass number of the parent and daughter nuclei remain the same while the atomic number of the daughter nucleus is greater than that of its parent by one unit.

Hence, in beta emission, the daughter nucleus is found one pace to the right of the parent in the periodic table.

3 0

3 years ago

Predict the major product of the following reaction of 1-methylcyclohexene with dilute HCl in H2O?

Scrat [10]

Answer:

1-chloro-1-methylcyclohexane

Explanation:

The hydrocarbons with one double bond are called alkenes and are named with the suffix "ene". The alkenes, such as 1-methylcyclohexene, react better in an addition reaction. The double bond will be broken, and the substitutes will be placed at them.

In the reaction with HCl, H and Cl will be added to the carbons of the broken bond. The major product is formed when H is put at the carbon less substituted. Thus, the product will be the one given below, 1-chloro-1-methylcyclohexane.

7 0

3 years ago

In 1808, John Dalton proposed a series of statements regarding the atom that became known as Dalton's postulates or Dalton's ato

Oduvanchick [21]

Answer:

The all 4 the given statements are part of Dalton's atomic theory.

Explanation:

Dalton's postulates or Dalton's atomic theory:

Matter is made up of small particles termed as atom.
Atoms are indivisible particle.
Atoms of different element have different masses and properties.
Atoms of the same element have the identical size, mass, and structure.
During chemical reaction, rearrangement of atoms takes place.
Atoms of different different combines together to form new compounds in simple whole number ratio.

6 0

3 years ago