1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Varvara68 [4.7K]
2 years ago
15

140 g of KCl is dissolved in 600 mL of water. What is the molarity?

Chemistry
1 answer:
FromTheMoon [43]2 years ago
7 0

Answer:

\boxed {\boxed {\sf molarity \approx 3 \ M \ KCl}}

Explanation:

Molarity is a measure of concentration in moles per liter. The formula is:

molarity= \frac{moles \ of \ solute}{liters \ of \ solution}

We are given grams of solute and liters of solution, so we must convert both before calculating molarity.

<h3>1. Convert Grams to Moles</h3>

We convert grams to moles using the molar mass. This value is found on the Periodic Table. It is the same as the atomic mass, but the units are grams per mole (g/mol) instead of atomic mass units (amu).

We have the compound KCl, so we look up the molar masses of the individual elements.

  • Potassium (K): 39.098 g/mol
  • Chlorine (Cl): 35.45 g/mol

The compound does not contain subscripts, so we can add the molar masses together to find the molar mass of the compound.

  • Potassium chloride (KCl): 39.098+ 35.45= 74.548 g/mol

Use the molar mass as a ratio.

\frac {74.548 \ g\ KCl}{1 \ mol \ KCl}

Multiply by 140 grams of KCl.

140 \ g\ KCl*\frac {74.548 \ g\ KCl}{1 \ mol \ KCl}

Flip the ratio so the units of grams of KCl cancel.

140 \ g\ KCl*\frac{1 \ mol \ KCl} {74.548 \ g\ KCl}

140 *\frac{1 \ mol \ KCl} {74.548 }

1.877984654 \ mol \ KCl

<h3>2. Convert Milliliters to Liters</h3>

1 liter contains 1000 milliliters. Create another ratio.

\frac{ 1 \ L}{1000 \ mL}

Multiply by 600 milliliters (the value we are converting).

600 \ mL *\frac{ 1 \ L}{1000 \ mL}

The units of milliliters cancel.

600 \ *\frac{ 1 \ L}{1000 }

0.6 \ L

<h3>3. Calculate Molarity</h3>

Now we know the moles of solute and the liters of solution.

  • 1.877984654  mol  KCl and 0.6 L

Substitute the values into the molarity formula.

molarity= \frac {1.877984654 \ mol \ KCl}{0.6 \ L}

molarity= 3.129974424 \ mol \ KCl/L

The original measurements of grams and milliliters have 2 and 1 significant figures. We must round our answer to the least number of sig figs: 1.

For the number we found, that is the ones place. The 1 in the tenths place tells us to leave the 3 in the ones place.

molarity \approx 3 \ mol \ KCl/L

1 mole per liter is equal to 1 molar or M. Convert the units.

molarity \approx 3 \ M \ KCl

The molarity is approximately <u>3 M KCl.</u>

You might be interested in
The equilibrium constant for the reaction of carbon monoxide with water is 1.845. if 1.00 mol of each reactant is placed in a 2.
SpyIntel [72]
[CO] = 1 mol / 2L = 0.5 M

[
According to the equation:

and by using the ICE table:

             CO(g) + H2O(g) ↔   CO2(g) + H2(g)

initial     0.5            0.5                    0          0

change  -X              -X                   +X         +X
     
Equ       (0.5-X)       (0.5-X)                     X            X

when Kc = X^2 * (0.5-X)^2

by substitution:

1.845 = X^2 * (0.5-X)^2  by solving for X 

∴X = 0.26

∴ [CO2] = X = 0.26
4 0
2 years ago
What is the hardest mineral listed here? <br> A. quartz B. calcite C. gypsum D. corundum
a_sh-v [17]
The answer would be D. The only minerals harder than corundum is diamond.
3 0
3 years ago
Read 2 more answers
Do Alkali Metal Compounds form precipitates? And Why?
Alexeev081 [22]

Answer:

Alkali metal hydroxides can be used to test the identity of metals in certain salts. The colour of the precipitate will help identify the metal : Calcium hydroxide is soluble; no precipitate is formed.

6 0
2 years ago
Hydrofluoric acid, hf, has a ka of 6.8 × 10−4. what are [h3o+], [f−], and [oh−] in 0.710 m hf?
STALIN [3.7K]

Answer:

[H₃O⁺] = [F⁻] = 2.2 x 10⁻² M. & [OH⁻] = 4.55 x 10⁻¹³.

Explanation:

  • For a weak acid like HF, the dissociation of HF will be:

<em>HF + H₂O ⇄ H₃O⁺ + F⁻.</em>

[H₃O⁺] = [F⁻].

<em>∵ [H₃O⁺] = √Ka.C,</em>

Ka = 6.8 x 10⁻⁴, C = 0.710 M.

∴ [H₃O⁺] = √Ka.C = √(6.8 x 10⁻⁴)(0.710) = 2.197 x 10⁻² M ≅ 2.2 x 10⁻² M.

<em>∴ [H₃O⁺] = [F⁻] = 2.2 x 10⁻² M.</em>

<em></em>

∵ [H₃O⁺][OH⁻] = 10⁻¹⁴.

<em>∴ [OH⁻] = 10⁻¹⁴/[H₃O⁺]</em> = 10⁻¹⁴/(2.2 x 10⁻²) = <em>4.55 x 10⁻¹³.</em>

6 0
2 years ago
Nonmetals gain electrons under certain conditions to attain a noble gas electron configuration. How many electrons must be gaine
gogolik [260]

Answer:

1

Explanation:

For non metals to attain a noble gas configuration, they gain the number of electrons needed to attain the noble gas configuration of the noble gas at the end of their periods. This means that these non metals would only take up the configuration of the last element on their periods which of course is always a noble gas.

The last element on the hydrogen period or more conservatively the only other element on the hydrogen period is helium, with an atomic number of 2. The atomic number is the number of protons in he nucleus of an atom. For an electrically neutral atom, the number of electrons equal the number of protons.

Hence we can deduce that helium has 2 electrons while hydrogen has one electron. Thus for it to attain the configuration of helium, it just needs to gain one more electron

6 0
2 years ago
Other questions:
  • You have a mixture that contains 0.380 moles of Ne(g), 0.250 moles of He(g), and 0.500 moles CH4(g) at 400 K and 7.25 atm. What
    11·1 answer
  • How many half-lives must elapse until 84 % of a radioactive sample of atoms has decayed? -g?
    11·1 answer
  • When acetic anhydride is dissolved in water, it forms acetic acid according to the balanced chemical reaction shown below. calcu
    5·1 answer
  • Express 0.08010 in exponential notation to the proper significant figures
    11·1 answer
  • If you combined neon, argon and helium together, what would you expect to happen?
    11·1 answer
  • Why does water dissolve sugar ? Explain your answer !
    15·1 answer
  • 6.Which of the following is NOT true about the lens?
    7·1 answer
  • ¿Cuánto calor es necesario suministrar a 2 kilogramos de aluminio para que eleve su temperatura 20°C?
    10·1 answer
  • Which of the following is NOT needed for photosynthesis to take place?
    8·2 answers
  • HElp i am stuck and i am not sure
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!