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1 year ago

Briefly account for the following relative values:

Chemistry

1 answer:

Sedbober [7]1 year ago

4 0

The melting points of Na and K are 89°C and 63°C, respectively because of weak attractive force.

Sodium and potassium belongs to group 1.

<h3>What is atomic radii? </h3>

The distance of the outermost shell to the nucleus is called atomic radii.

As we go down the group, new shell is added which means number of shell increase as we go down the group.

Due to increase in the number of shells, the distance of outermost shell to the positively charged nucleus increase.Due to which atomic radius increase.

Due to increase in the atomic radii, the nuclear force of attraction on outermost shell decreases down the group.

This decrease in the nuclear force of attraction cause decrease in the melting point.

We can say that, melting point of a compound is inversely proportional to the atomic radii.

Therefore, melting point of sodium is less than the potassium atom.

Thus, we concluded that the melting points of Na and K are 89°C and 63°C, respectively because of weak attractive force.

learn more about melting point:

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Which statement is true of a heterogeneous mixture but not of a

Natalka [10]

Answer:

Explanation:

well heterogenous mixtures are not uniformly distributed these meaning whatever components are "mixed" can be seperated easily

a example of this can be

Soil, oil in water, ice in water

while Homogeneous mixture cannot be seen seperated

4 0

3 years ago

Which solution below has the highest concentration of hydroxide ions?a. pH= 3.21b. pH= 7.00c. pH= 7.93d. pH= 12.59e. pH= 9.82

Sloan [31]

Answer:

<em>The solution that has the highest concentration of hydroxide ions is </em><u>d. pH = 12.59.</u>

Explanation:

You can solve this question using just some chemical facts:

pH is a measure of acidity or alkalinity: the higher the pH the lower the acidity and the higher the alkalinity.
The higher the concentration of hydroxide ions the lower the acidity or the higher the alkalinity of the solution, this is the higher the pH.

Hence, since you are asked to state the solution with the highest concentration of hydroxide ions, you just pick the highest pH. This is the option d, pH = 12.59.

These mathematical relations are used to find the exact concentrations of hydroxide ions:

pH + pOH = 14 ⇒ pOH = 14 - pH

pOH = - log [OH⁻] ⇒ $[OH^-]=10^{-pOH}$

Then, you can follow these calculations:

Solution pH pOH [OH⁻]

a. 3.21 14 - 3.21 = 10.79 antilogarithm of 10.79 = 1.6 × 10⁻¹¹

b. 7.00 14 - 7.00 = 7.00 antilogarithm of 7.00 = 10⁻⁷

c. 7.93 14 - 7.93 = 6.07 antilogarithm of 6.07 = 8.5 × 10⁻⁷

d. 12.59 14 - 12.59 = 1.41 antilogarithm of 1.41 = 0.039

e. 9.82 14 - 9.82 = 4.18 antilogarithm of 4.18 = 6.6 × 10⁻⁵

From which you see that the highest concentration of hydroxide ions is for pH = 12.59.

5 0

2 years ago

From a scientific viewpoint, why do many desert dwellers elect to wear white or light-colored garments

alexandr1967 [171]

Darker colors absorb sunlight more, so it will become hotter. Lighter colored clothes will better reflect sun so they will be less hot.

Hope that helped

7 0

3 years ago

The density of a 3.37M MgCl2 (FW = 95.21) is 1.25 g/mL. Calulate the molality, mass/mass percent, and mass/volume percent. So fa

Dafna1 [17]

Answer : The molality, mass/mass percent, and mass/volume percent are, 0.0381 mole/Kg, 25.67 % and 32.086 % respectively.

Solution : Given,

Density of solution = 1.25 g/ml

Molar mass of $MgCl_2$ (solute) = 95.21 g/mole

3.37 M magnesium chloride means that 3.37 gram of magnesium chloride is present in 1 liter of solution.

The volume of solution = 1 L = 1000 ml

Mass of $MgCl_2$ (solute) = 3.37 g

First we have to calculate the mass of solute.

$\text{Mass of }MgCl_2=\text{Moles of }MgCl_2\times \text{Molar mass of }MgCl_2$

$\text{Mass of }MgCl_2=3.37mole\times 95.21g/mole=320.86g$

Now we have to calculate the mass of solution.

$\text{Mass of solution}=\text{Density of solution}\times \text{Volume of solution}=1.25g/ml\times 1000ml=1250g$

Mass of solvent = Mass of solution - Mass of solute = 1250 - 320.86 = 929.14 g

Now we have to calculate the molality of the solution.

$Molality=\frac{\text{Mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Mass of solvent}}=\frac{3.37g\times 1000}{95.21g/mole\times 929.14g}=0.0381mole/Kg$