0.459 moles of Mg(OH)2

What is the molarity of a solution that contains 224 grams of KOH in 2<br> liters of solution?

adelina 88 [10]

Answer:

$\boxed {\boxed {\sf 2 \ M \ KOH}}$

Explanation:

Molarity is a measure of concentration in moles per liter.

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

The first step is to convert the amount of grams given to moles. The molar mass is used. This found on the Periodic Table and it's the same value as the atomic mass, but the units are grams per mole.

We have 224 grams of KOH. Look up the molar masses for the individual elements.

Potassium (K): 39.098 g/mol
Oxygen (O): 15.999 g/mol
Hydrogen (H): 1.008 g/mol

Since the compound's formula has no subscripts, 1 formula unit has 1 atom of each element. We can simply add the molar masses together to find KOH's molar mass.

KOH: 39.098 + 15.999 + 1.008=56.105 g/mol

Use this number as a ratio.

$\frac {56.105 \ g\ KOH}{1 \ mol \ KOH}$

Multiply by the value we are converting: 224 g KOH

$224 \ g \ KOH *\frac {56.105 \ g\ KOH}{1 \ mol \ KOH}$

Flip the ratio so the units of grams KOH cancel.

$224 \ g \ KOH *\frac {1 \ mol \ KOH}{56.105 \ g\ KOH}$

$224 *\frac {1 \ mol \ KOH}{56.105}$

$\frac {224}{56.105} \ mol \ KOH$

$3.992514036 \ mol \ KOH$

<h3>2. Calculate Molarity </h3>

Remember molarity is moles per liter.

$molarity = \frac{moles}{liters}$

We just calculated the moles and we know there are 2 liters of solution.

$molarity = \frac{ 3.992514036 \ mol \ KOH}{ 2 \ L}$

$molarity= 1.996257018 \ mol \ KOH/ L$

<h3>3. Round and Convert Units </h3>

First, let's round. The original values have 3 and 1 significant figures. We go with the lowest number: 1. For the number we found, that is the ones place.

1.<u>9</u>96257018

The 9 in the tenths place tells us to round to 1 up to a 2

$2 \ mol \ KOH/ L$

Next, convert units. 1 mole per liter is equal to 1 molar or M.

$2 \ M \ KOH$

The molarity of the solution is <u>2 M KOH</u>

6 0

3 years ago

Read 2 more answers

Consider the dissolution of 1.50 grams of salt XY in 75.0 mL of water within a calorimeter. The temperature of the water decreas

-BARSIC- [3]

Answer:

The quantity of heat lost by the surroundings is 258,5J

Explanation:

The dissolution of salt XY is endothermic because the water temperature decreased.

The total heat consumed by the dissolution process is:

4,184 J/g°C × (75,0 + 1,50 g) × 0,93°C = 297,7 J

This heat is consumed by the calorimeter and by the surroundings.

The heat consumed by the calorimeter is:

42,2 J/°C × (0,93°C) = 39,2 J

That means that the quantity of heat lost by the surroundings is:

297,7J - 39,2J = <em>258,5 J</em>

I hope it helps!

8 0

3 years ago

10. How many elements do all the "d" orbital span (go across) in each period? (circle your answer)

Tamiku [17]

S orbits hold 2 electrons P orbits hold 6 electrons D orbits hold 10 electrons and F orbits hold 14 electrons

8 0

3 years ago

At a certain temperature, the ph of a neutral solution is 7.78. what is the value of kw at that temperature? express your answer

Strike441 [17]

Given the pH of the solution, we can determine [H⁺].

pH = -log[H⁺]
[H⁺] = 10⁻⁷·⁷⁸
[H⁺] = 1.659586907 x 10⁻⁸ M

We also know that pOH = 14 - pH. Thus, the pOH is 6.22. Given the pOH of the solution, we can determine [OH⁻].

pOH = -log[OH⁻]
[OH⁻] = 10⁻6.22
[OH⁻] = 6.02559586 x 10⁻⁷ M

The ionic product of water Kw, can then be calculated using the following equation.

Kw = [H⁺][OH⁻]
Kw = (1.659586907 x 10⁻⁸)(6.02559586 x 10⁻⁷)
Kw = 1.0 x 10⁻¹⁴

8 0

4 years ago

What is the mass of 8.83 x 10^23 formula units of Iron (III) oxide, Fe2O3?

zepelin [54]

Answer:

234.68g

Explanation:

We understood from Avogadro's hypothesis that 1mole of any substance contains 6.02x10^23 atoms. Therefore, 1mole of Fe2O3 also contains 6.02x10^23 atoms

1 mole of Fe2O3 = (56x2) + (16x3) = 112 + 48 = 160g

Now, if 160g of Fe2O3 contains 6.02x10^23 atoms,

Therefore Xg of Fe2O3 will contain 8.83×10^23 atoms i.e

Xg of Fe2O3 = (160x8.83×10^23)/6.02x10^23 = 234.68g

8 0

3 years ago