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3 years ago

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Which of the following would be IRRELEVANT when choosing a material to use for making overhead cables for distributing electrici

ty long distances?
a) Density
b) Thermal Conductivity
c)Ductile
d)Electrical Conducivity

1 answer:

yawa3891 [41]3 years ago

3 0

A. Density is the correct answer

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A heavy textbook and a QOD journal sit on the edge of your desk. Which has more gravitational potential energy?

fenix001 [56]

The textbook Would most likely have more gravitational potential energy because it is heavier. Things that are heavier have a larger gravitational pull and are pulled to the earth faster

4 0

3 years ago

Be sure to answer all parts. What is the [H3O+] and the pH of a buffer that consists of 0.26 M HNO2 and 0.89 M KNO2? (K, of HNO2

Aleksandr-060686 [28]

Answer : The $H_3O^+$ ion concentration is, $1.12\times 10^{-3}M$ and the pH of a buffer is, 2.95

Explanation : Given,

$K_a=7.1\times 10^{-4}$

Concentration of $HNO_2$ (weak acid)= 0.26 M

Concentration of $KNO_2$ (conjugate base or salt)= 0.89 M

First we have to calculate the value of $pK_a$ .

The expression used for the calculation of $pK_a$ is,

$pK_a=-\log (K_a)$

Now put the value of $K_a$ in this expression, we get:

$pK_a=-\log (7.1\times 10^{-4})$

$pK_a=4-\log (7.1)$

$pK_a=3.15$

Now we have to calculate the pH of the solution.

Using Henderson Hesselbach equation :

$pH=pK_a+\log \frac{[Salt]}{[Acid]}$

$pH=pK_a+\log \frac{[KNO_2]}{[HNO_2]}$

Now put all the given values in this expression, we get:

$pH=3.15+\log (\frac{0.89}{0.26})$

$pH=2.95$

The pH of a buffer is, 2.95

Now we have to calculate the $H_3O^+$ ion concentration.

$pH=-\log [H_3O^+]$

$2.95=-\log [H_3O^+]$

$[H_3O^+]=1.12\times 10^{-3}M$

The $H_3O^+$ ion concentration is, $1.12\times 10^{-3}M$

4 0

3 years ago

Calculate the mass percent of calcium chloride in 8.87 g of calcium chloride in 65.1 g of water

zhannawk [14.2K]

Answer:

11.99 % ≅ 12.0%.

Explanation:

∵ mass % = [mass of solute/mass of solution] x 100.

mass of solute (CaCl₂) = 8.87 g & mass of solution = 8.87 g + 65.1 g = 73.97 g.

<em>∴ mass % of (CaCl₂) = [mass of solute/mass of solution] x 100 </em>= ( 8.87 g/ 73.97 g) x 100 = <em>11.99 % ≅ 12.0%.</em>

7 0

3 years ago

The ksp of calcium carbonate, caco3, is 3.36 × 10-9 m2. calculate the solubility of this compound in g/l.

maw [93]

CaCO₃ partially dissociates in water as Ca²⁺ and CO₃²⁻. The balanced equation is,
CaCO₃(s) ⇄ Ca²⁺(aq) + CO₃²⁻(aq)
Initial Y - -
Change -X +X +X
Equilibrium Y-X X X

Ksp for the CaCO₃(s) is 3.36 x 10⁻⁹ M²

Ksp = [Ca²⁺(aq)][CO₃²⁻(aq)]
3.36 x 10⁻⁹ M² = X * X
3.36 x 10⁻⁹ M² = X²
X = 5.79 x 10⁻⁵ M

Hence the solubility of CaCO₃(s) = 5.79 x 10⁻⁵ M
= 5.79 x 10⁻⁵ mol/L

Molar mass of CaCO₃ = 100 g mol⁻¹

Hence the solubility of CaCO₃ = 5.79 x 10⁻⁵ mol/L x 100 g mol⁻¹
= 5.79 x 10⁻³ g/L

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3 years ago

Question 4 options: what is the volume of 1.2 moles of water vapor at stp?

Law Incorporation [45]

What is the volume of 1.2 moles of water vapor at STP?
The answer is 26.9

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3 years ago