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Alex
3 years ago
9

KCl is an ionic salt with a formula weight of 74.54 g/mole. A 1.417 M (mole/liter) KCl solution has a density of 1064.5 grams/li

ter at 20.0 OC. Use the Molarity and the formula weight to find the mass (g) of salt in one liter. Then, find the mass (g and kg) of water in one liter of the solution as the difference between the solution mass and the KCl mass. Include the conversion factor. Determine the molality (m), or moles of salt per kg of water, by dividing the moles of salt in one liter by the kg of water in one liter. Show all units and use proper significant figures. (
Chemistry
1 answer:
xenn [34]3 years ago
3 0

Answer:

Mass of the salt:  105.6g of KCl.

Mass water: 958.9g of water.

Molality: 1.478m.

Explanation:

<em>Mass of the salt:</em>

In 1L, there are 1.417 moles. In grams:

1.417 moles KCl * (74.54g / mol) = 105.6g of KCl

<em>Mass of the water:</em>

We can determine the mass of solution (Mass of water + mass KCl) by multiplication of the voluome (1L and density 1064.5g/L), thus:

1L * (1064.5g / L) = 1064.5g - Mass solution.

Mass water = 1064.5g - 105.6g = 958.9g of water

<em>Molality:</em>

Moles KCl = 1.417 moles KCl.

kg Water = 958.9g = 0.9589kg.

Molality = 1.417mol / 0.9589kg = 1.478m

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Mature elephants consume an average of 600 pounds of food per day. If an elephant
MAXImum [283]

Answer:

\large \boxed{\text{4 600 000 kg or 4600 Mg}}

Explanation:

1. Calculate the adult life

If the elephant is an adult from its 10th birthday until the day before its 56th birthday, its  

Adult life = 55 - 10 + 1 = 46 yr

2. Convert years to days

\text{Adult life} = \text{46 yr} \times \dfrac{\text{365.25 da}}{\text{1 yr}} = \text{16 800 da}

3. Convert days to pounds of feed

\text{Feed} = \text{16 800 da} \times \dfrac{\text{600 lb}}{\text{1 da}} = 1.01 \times 10^{7} \text{ lb}

4. Convert pounds to kilograms and megagrams

\text{Feed} =1.01 \times 10^{7} \text{ lb} \times \dfrac{\text{1 kg}}{\text{2.20 lb}} =\textbf{4 600 000 kg} = \textbf{4600 Mg}\\\\\text{The elephant will eat $\large \boxed{\textbf{4 600 000 kg or 4600 Mg}}$ of food.}

Note: The answer can have only two significant figures because that is all you gave for age of the elephant.

5 0
3 years ago
If a buffer solution is 0.220 M in a weak acid ( Ka=7.4×10−5) and 0.540 M in its conjugate base, what is the pH?
valkas [14]

Answer: the pH of the solution is 4.52

Explanation:

Consider the weak acid as Ha, it is dissociated as expressed below

HA     H⁺  +  A⁻

the Henderson -Haselbach equation can be expressed as;

pH = pKa + log( [A⁻] / [HA])

the weak acid is dissociated into H⁺ and A⁻ ions in the solution.

now the conjugate base of the weak acid HA is

HA(aq) {weak acid}     H⁺(aq)  +  A⁻(aq) {conjugate base}

so now we calculate the value of Kₐ as well as pH value by substituting the values of the concentrations into the equation;

pKₐ = -logKₐ

pKₐ = -log ( 7.4×10⁻⁵ )

pKₐ = 4.13

now thw pH is

pH = pKₐ  + log( [A⁻] / [HA])

pH = 4.13 + log( [0.540] / [0.220])

pH = 4.13 + 0.3899

pH = 4.5199 = 4.52

Therefore the pH of the solution is 4.52

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3 years ago
A scientist investigates on two unknown solutions. Which is not a scientific experiment she can perform on the solutions?
Serga [27]
As you can search and read the definition of a scientific experiment is the process of testing and finding the truth through this scientific method. Thus, all items are considered scientific experiment except for item "c" Ask her coworkers which solution they thick is better.
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2 years ago
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3 years ago
What do Potassium and Krypton have in common and what are their differences based on their location on the periodic table?
andreev551 [17]

Common based on their location in Periodic Table;

Potassium has an atomic number 19. Its electronic configuration is as follow;

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And Krypton has an atomic number of 36. Its electronic configuration is as follow;

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It is concluded that both Potassium and Krypton has their valence electrons in 4rth shell or they have same Principle Quantum Number.

Difference based on their location in Periodic Table;

As observed in electronic configuration Potassium has one valence electron in its valence shell (i.e. 4s¹) while, Krypton has eight valence electrons in its valence shell (i.e. 4s², 4p⁶). Therefore, they are different in the number of valence electrons.

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