PLEASE HELP!!

A student used 1.168g of an unknown weak acid and titrated it against 28.75 mL of 0.105M NaOH to reach the equivalence point. Wh

Vaselesa [24]

Answer:

The molar mass of the unknown acid is 386.8 g/mol

Explanation:

Step 1: Data given

Mass of the weak acid = 1.168 grams

volume of NaOH = 28.75 mL = 0.02875 L

Molarity of NaOH = 0.105 M

Since we only know 1 equivalence point, we suppose the acid is monoprotic

Step 2: Calculate moles NaOH

Moles NaOH = molarity NaOH * volume NaOH

Moles NaOH = 0.105 M * 0.02875 L

Moles NaOH = 0.00302 moles

We need 0.00302 moles of weak acid to neutralize the NaOH

Step 3: Calculate molar mass of weak acid

Molar mass = mass / moles

Molar mass = 1.168 grams / 0.00302 moles

Molar mass = 386.8 g/mol

The molar mass of the unknown acid is 386.8 g/mol

3 0

3 years ago

A sample of carbon monoxide gas is initially in a 5858 mL container. The gas is then moved to 3.29 L container at a temperature

Doss [256]

Answer:

d i took the test

Explanation:

5 0

3 years ago

A solution made by dissolving 33 mg of insulin in 6.5 mL of water has an osmotic pressure of 15.5 mmHg at 25°C. Calculate the mo

Liula [17]

<u>Answer:</u> The molar mass of the insulin is 6087.2 g/mol

<u>Explanation:</u>

To calculate the concentration of solute, we use the equation for osmotic pressure, which is:

$\pi=iMRT$

Or,

$\pi=i\times \frac{\text{Mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Volume of solution (in mL)}}\times RT$

where,

$\pi$ = osmotic pressure of the solution = 15.5 mmHg

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

Mass of solute (insulin) = 33 mg = 0.033 g (Conversion factor: 1 g = 1000 mg)

Volume of solution = 6.5 mL

R = Gas constant = $62.364\text{ L.mmHg }mol^{-1}K^{-1}$

T = temperature of the solution = $25^oC=[273+25]=298K$

Putting values in above equation, we get:

$15.5mmHg=1\times \frac{0.033\times 1000}{\text{Molar mass of insulin}\times 6.5}\times 62.364\text{ L.mmHg }mol^{-1}K^{-1}\times 298K\\\\\text{molar mass of insulin}=\frac{1\times 0.033\times 1000\times 62.364\times 298}{15.5\times 6.5}=6087.2g/mol$

Hence, the molar mass of the insulin is 6087.2 g/mol

8 0

3 years ago

An atom of Fe has 30 neutrons. What is the mass number of this atom?

SVETLANKA909090 [29]

Answer:

56

Explanation:

The mass number of an atom is a sum of its number of protons and neutrons. Iron (Fe) has an atomic number of 26. This means that it has 26 protons. Since we know it has 26 protons and are told it has 30 neutrons. The mass number of this atom of Iron is 26+30 = 56

Hope this helped!

7 0

3 years ago

Zn +

saul85 [17]

Answer:

1. Theoretical yield = 2.03g

2. Actual yield 1.89g

Explanation:

Let us write a balanced equation. This is illustrated below:

Zn + 2HCI —> ZnCl2 + H2

Molar Mass of HCl = 1 +35.5 = 36.5g/mol

Mass of HCl from the balanced equation = 2 x 36.5 = 73g

Molar Mass of H2 = 2x1 = 2g/mol

1. From the equation,

73g of HCl produced 2g of H2.

Therefore, 74g of HCl will produce = (74 x 2)/73 = 2.03g

Therefore, theoretical yield = 2.03g

2. %yield = 93%

Theoretical yield = 2.03g

Actual yield =?

%yield = Actual yield /Theoretical yield x100

Actual yield = %yield x theoretical yield

Actual yield = 93% x 2.03 = (93/100)x2.03 = 1.89g

Actual yield =1.89g

4 0

4 years ago