Ask question

Ask question

All categories

2 years ago

15

A chemistry student needs 90.00 g of thiophene for an experiment. She has available 0.50 kg of a 12.3% w/w solution of thiophene

in ethanol.
Calculate the mass of solution the student should use. If there's not enough solution, press the 'No solution" button
Round your answer to 3 significant digits. Put the answer in terms of the amount of grams.

1 answer:

jok3333 [9.3K]2 years ago

7 0

<u>Answer:</u> The correct answer is No solution.

<u>Explanation:</u>

We are given:

Given mass of thiophene for the experiment = 90.00 g

12.3% w/w solution of thiophene

This means that 12.3 g of thiophene is present in 100 g of solution

Applying unitary method:

If 12.3 g of thiophene is present in 100 g of solution

So, 90.00 g of thiophene will be present in $\frac{100g}{12.3g}\times 90.00g=731.7g$ of solution

Converting it into kilograms:

1 kg = 1000 g

So, 731.7 g = 0.7317 kg

As the given amount of solution is 0.50 kg which is less than the required amount.

Thus, there is not enough solution the student should use.

You might be interested in

What is the name of the compound with the formula NaOH ?

vladimir2022 [97]

Answer:

Sodium hydroxide

Explanation:

Sodium hydroxide ( NaOH ) -

Sodium hydroxide is an inorganic compound , and is also called caustic soda and lye .

It is an ionic compound , which is white in color and is in solid state .

The cation and anion of this salt are the sodium cation Na⁺ and the hydroxide anions OH⁻ .

<u>It is highly basic in nature and is soluble in water , and when left open in air it can readily absorb moisture from the air , to form a hydrated sodium hydroxide .</u>

4 0

3 years ago

How is helium different from other noble gases?

Slav-nsk [51]

Helium only possesses two valence electrons, while the other noble gasses posses eight

3 0

2 years ago

Given the chemical reaction: Hg2+(aq) + Cu(s) + Hg(s) + Cu2+(aq)

Pavel [41]

Answer: When the reaction reaches equilibrium, the cell potential will be 0.00 V

Explanation:

Equilibrium state is the state when reactants and products are present but the concentrations does not change with time.

The equilibrium is dynamic in nature and the reactions are continuous in nature. Rate of forward reaction is equal to the rate of backward reaction.

The standard emf of a cell is related to Gibbs free energy by following relation:

$\Delta G=-nFE^0$

The Gibbs free energy is related to equilibrium constant by following relation:

$\Delta G=-2.303RTlog K$

For equilibrium $\Delta G=0$

Thus $0=-nFE^0$

$E^0=0$

Thus When the reaction reaches equilibrium, the cell potential will be 0.00 V

5 0

3 years ago

Gold has a density of about 20g/mL. If I measured out 2mL of gold, I would expect it to have a mass of about ___ grams.

yan [13]

The answer is 40 grams. If gold is 20 grams per mL and you have 2 mLs, you get 40 grams of gold. Just add 20 + 20 or multiply 2 x 20 to get 40.

4 0

3 years ago

What will be the final temperature of the solution in a coffee cup calorimeter if a 50.00 mL sample of 0.250 M HCl(aq) is added

padilas [110]

Answer:

21.21°C will be the final temperature of the solution in a coffee cup calorimeter.

Explanation:

$HCl+NaOH\rightarrow H_2O+NaCl$

$\Delta H$ = enthalpy change = -57.2 kJ/mol of NaOH

Moles of sodium hydroxide = n

Molarity of the NaOH = 0.250 M

Volume of NaOH solution = V = 50.00 mL = 0.050 L

$n=Molarity\times V=0.250 M\times 0.050 L= 0.0125 mol$

Moles of HCl = n'

Molarity of the HCl= 0.250 M

Volume of HCl solution = V' = 50.00 mL = 0.050 L

$n'=Molarity\times V=0.250 M\times 0.050 L= 0.0125 mol$

Since 1 mole of Hcl reacts with 1 mole of NaoH. Then 0.0125 mole of HCl will react with 0.0125 mole of NaOH.

The enthalpy change during the reaction.

$\Delta H=-\frac{q}{n}$

$q=\Delta H\times n=-57.2 kJ/mol \times 0.0125 mol= -0.715 kJ=-715 J$

q = heat released on reaction= -715 J

now, we calculate the heat gained by the solution.:

Q= -q = -(-715 J) = 715 J

m = mass of the solution = ?

Volume of the solution formed by mixing, v = 50.00 ml + 50.00 mL = 100.00 mL

Density of the solution = density of water = d = 1 g/mL

$mass=density\times volume=d\times v=1 g/ml \times 100.00 ml=100 g$

m = 100 g

q = heat gained = ?

c = specific heat = $4.18 J/^oC$

$T_{f}$ = final temperature = ?

$T_{i}$ = initial temperature = $19.50^oC$

$Q=mc\times (T_{f}-T_{i})$

Now put all the given values in the above formula, we get:

$715 J=100 g\times 4.18J/^oC\times (T_f-19.50)^oC$

$T_f=21.21 ^oC$

21.21°C will be the final temperature of the solution in a coffee cup calorimeter.

5 0

3 years ago