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A solution is formed by mixing 15.2 g KOH into

nikitadnepr [17]

Answer:

There are approximately $0.271\; \rm mol$ of formula units in that $\rm 15.2\; g$ of $\rm KOH$ (the solute of this solution.)

Explanation:

A solution includes two substances: the solute and the solvent. Note the solution here contains significantly more water than $\rm KOH$ . Hence, assume that water is the solvent (as it is in many other solutions.)

The (molar) formula mass of $\rm KOH$ is necessary for finding the number of moles of

One $\rm K$ atom,
One $\rm O$ atom, and
One $\rm H$ atom.

The formula mass of $\rm KOH$ will thus be the sum of:

The mass of one mole of $\rm K$ atoms,
The mass of one mole of $\rm O$ atoms, and
The mass of one mole of $\rm H$ atoms.

On the other hand, the mass (in grams) of one mole of atoms of an element is (numerically) the same as its relative atomic mass. The relative atomic mass data can be found on most modern periodic tables.

Relative atomic mass data from a modern periodic table:

$\rm K$ : $39.098$ .
$\rm O$ : $15.999$ .
$\rm H$ : $1.008$ .

For example, the relative atomic mass of $\rm K$ (potassium, atomic number $19$ ) is $39.098$ (3 sig. fig.) Hence, the mass of one mole of

The formula mass of $\rm KOH$ is the sum of these three masses:

$\begin{aligned}& M(\mathrm{KOH}) \\ &\approx 39.098 + 15.999 + 1.008 \\ &= 56.105\; \rm g \cdot mol^{-1}\end{aligned}$ .

The number of moles of $\rm KOH$ formula units in this $15.2\; \rm g$ sample would be:

$\begin{aligned}n &= \frac{m(\mathrm{KOH})}{M(\mathrm{KOH})} \\ &\approx \frac{15.2\; \rm g}{56.105\; \rm g \cdot mol^{-1}} \approx 0.271\; \rm mol \end{aligned}$ .

6 0

3 years ago

What is the ph of a solution which is 0. 023 m in weak base and 0. 037 m in the conjugate weak acid ( a = 7. 1 × 10^−6)?

Rzqust [24]

The pH of a solution which is 0.023 m in weak base and 0 037 m in the conjugate weak acid whose Ka= 7.1 × 10⁻⁶ is 4.93.

pH determines the amount of hydrogen and hydroxide ions in a solution. It is the negative logarithm of hydrogen ion concentration.

Given,

Ka= 7.1 × 10⁻⁶

Weak base = 0.023M

Acid = 0.037M

Using base dissociation constant, Ka we can calculate pKa by:

pKa = -log [Ka]

pKa = -log [7.1 × 10⁻⁶]

pKa = 5.15

A weak base and its conjugate acid are present in equal proportions in buffer solution. Using the Henderson-Hasselbalch equation, we can find out the pH of a buffer solution that constitutes a weak base and its conjugate acid.

Using Henderson-Hasselbalch equation,

pH = pKa + log [Weak base / acid]

pH = 5.15 + log [0.023 / 0.037]

pH = 5.15 + log[0.6]

pH = 5.15 - 0.22

pH = 4.93

Therefore, the pH of the solution is 4.93.

Learn more about pH here, brainly.com/question/22390063

#SPJ4

5 0

2 years ago

Suppose you were to read about a scientific statement based on data from hundreds of years of research and observation that appl

Dominik [7]

Answer:

theory

Explanation:

A theory has been tested and proven several times and oftentimes has a large amount of information, research, and evidence standing behind it.

Hope this helps! :)

5 0

3 years ago

How many molecules of water are in 3.8 moles of water?

Salsk061 [2.6K]

Answer:

2.29*10^24 molecules of water

Explanation:

1 molof water =6.022*10^23 molecules of water

therefore

molecules of water = 3.8*6.022*10^23

5 0

3 years ago

Read 2 more answers

A 32.14 gram sample of a hydrate of MnSO4 was heated thoroughly in a porcelain crucible, until its weight remained constant. Aft

amid [387]

Answer:

MnSO₄.7H₂O

Explanation:

To solve this question, we need to convert the mass of the dehydrated MnSO₄. The difference between mass of the hydrate and dehydrated compound is the mass of water. With the mass we can find the moles of water and the formula of the hydrate:

<em>Moles MnSO₄ -Molar mass: 151g/mol-:</em>

17.51g * (1mol / 151g) = 0.116 moles

<em>Moles H₂O -Molar mass: 18g/mol-:</em>

32.14g-17.51g = 14.63g * (1mol / 18g) = 0.813 moles

The ratio of moles MnSO₄: Moles H₂O represent the amount of water molecules in the hydrate:

0.813mol / 0.116mol = 7 molecules of water.

The hydrate formula is:

8 0

3 years ago