Which of the following is not a possible energy conversion for electricity?

Calculate the molarity of 0.50 mol MgCl2 in 750 ml of solution.

Vedmedyk [2.9K]

Answer : The correct answer for molarity of MgCl₂ solution is 0.67 M.

Molarity :

It expresses concentration of any solution . It can be defined as mole of solute present in volume of solution in Liter .

It uses unit M or $\frac{mol}{L}$

It can be formulated as :

$Molarity (\frac{mol}{L} ) = \frac{mole of solute (mol)}{volume of solution (L)}$

Given : mol of MgCl₂ (solute ) = 0.50 mol

Volume of solution = 750 mL

Following steps can be done :

Step 1 ) To convert volume of solution from mL to L

1 L = 1000 mL

$Volume of solution = 750 mL * \frac{1 L}{1000mL}$

Volume of solution = 0.750 L

Step 2) To find molarity

Plugging mole of solute and volume of solution in molarity formula as :

$Molarity = \frac{0.50 mol}{0.750 L }$

$Molarity = 0.67 \frac{mol}{L}$

Hence molarity of MgCl₂ solution is 0.67 M

4 0

4 years ago

Read 2 more answers

The Ka of hydrazoic acid (HN3) is 1.9 × 10-5 at 25.0 °C. What is the pH of a 0.40 M aqueous solution of HN3?

siniylev [52]

Answer:

The pH of the solution is 2.56.

Explanation:

Given :

Concentration (c) = 0.40 M

Acid dissociation constant = $K_a=1.9\times 10^{-5}$

The equilibrium reaction for dissociation of $HN_3$ (weak acid) is,

$HN_3+H_2O\rightleftharpoons N_3^{-}+H_3O^+$

initially conc. c 0 0

At eqm. $c(1-\alpha)$ $c\alpha$ $c\alpha$

Dissociation constant is given as:

$K_a=\frac{(c\alpha)(c\alpha)}{c(1-\alpha)}$

$1.9\times 10^{-5}=\frac{(0.40\alpha)(0.40\alpha)}{0.40(1-\alpha)}$

By solving the terms, we get value of $(\alpha)}$

$\alpha=0.00686832$

No we have to calculate the concentration of hydronium ion or hydrogen ion.

$[H^+]=c\alpha=0.4\times 0.00686832=0.002747 M$

Now we have to calculate the pH.

$pH=-\log [H^+]$

$pH=-\log (0.002747)$

$pH=2.56$

Therefore, the pH of the solution is, 2.56.

8 0

3 years ago

Why is the reaction of ethene with bromine called an addition reaction?.

antoniya [11.8K]

Answer: an addition reaction is one where two molecules react together to produce one. in this case a bromine molecule reacts with ethene and one of the bromine atoms is added to ethene

Explanation:

hope this helps :)

7 0

3 years ago

An aqueous solution that is 20.0 percent sulfuric acid (h2so4) by mass has a density of 1.105 g/ml. determine the molarity of th

GuDViN [60]

The definition of molarity is:

Molarity = moles of solute / total volume of solution in Liters

In this case, our solute is Sulfuric Acid. To solve this problem, let us assume a basis for calculation.

Let us say that,

Total mass of solution = 100 g

Therefore mass of H2SO4 = 20 g

The molar mass of H2SO4 = 98.079 g / mol

Calculating for number of moles of H2SO4:

number of moles = 20 g / (98.079 g / mol)

number of moles = 0.204 mol

Calculating for the volume of solution using the density:

total volume of solution = 100 g / (1.105 g / mL)

total volume of solution = 90.50 mL = 0.0905 L

Therefore the molarity is:

Molarity = 0.204 mol / 0.0905 L

Molarity = 2.2542 mol / L

Molarity = 2.25 M

3 0

4 years ago

The ΔHvap of a certain compound is 49.09 kJ·mol–1 and its ΔSvap is 53.69 J·mol–1·K–1. What is the boiling point of this compound

rusak2 [61]

Hey there !

Convert Joule to KJ :

1 j ---------------- 0.001 kj
53.69 j ----------- Kj

Kj = 53.69 * 0.001

=> 0.05369 Kj

T = ΔH / ΔS

T = 49.09 / 0.05369

T = 914.32ºC

3 0

3 years ago