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3 years ago

WHEN IN FRICTION not useful

Chemistry

1 answer:

Paladinen [302]3 years ago

6 0

Friction is not useful in Machinery sometimes, Since it leads to the wear and tear of machine parts.

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A red blood cell placed in saline solution will shrink.<br> True or false? Explain please?

Scorpion4ik [409]

Yes a red blood cell placed in a sline solution shrinks because of the process of osmosis.

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3 years ago

A solution of acetic acid has a pH of 3.45. What is the concentration of acetic acid in this solution? Ka for CH3COOH is 1.8×10-

Serjik [45]

Answer:

0.007 M

Explanation:

pH is defined as the negative logarithm of the concentration of hydrogen ions.

Thus,

pH = - log [H⁺]

The expression of the pH of the calculation of weak acid is:-

$pH=-log(\sqrt{k_a\times C})$

Where, C is the concentration = ?

Given, pH = 3.45

So, for $CH_3COOH$ , $K_a=1.8\times 10^{-5}$

$3.45=-log(\sqrt{1.8\times 10^{-5}\times C})$

$\log _{10}\left(\sqrt{1.8\cdot \:10^{-5}C}\right)=-3.45$

C = 0.007 M

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3 years ago

What pressure is required to achieve a co2 concentration of 7.90×10−2 m at 20∘c?

Savatey [412]

Answer:- 1.90 atm

Solution:- It is based on combined gas law equation, PV = nRT

In this equation, P is pressure, V is volume, n is moles of gas, R is universal gas constant and T is kelvin temperature.

If we divide both sides by V then:

$P=\frac{nRT}{V}$

We know that, molarity is moles per liter. So, in the above equation we could replace $\frac{n}{V}$ by molarity, M of the gas. The equation becomes:

P = MRT

T = 20 + 273 = 293 K

M = $7.9*10^-^2$

Let's plug in the values in the equation:

P = $(7.9*10^-^2)(0.0821)(293)$

P = 1.90 atm

So, the pressure of the gas is 1.90 atm.

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3 years ago

Why do plant cells need both chloroplasts and mitochondria?

nevsk [136]

They both perform photosynthesis and also cell respiration

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3 years ago

Read 2 more answers

What is the importance of "Sodium" for human health?

Aneli [31]

Answer:

Explanation:

Sodium is both an electrolyte and mineral. It helps keep the water (the amount of fluid inside and outside the body's cells) and electrolyte balance of the body. Sodium is also important in how nerves and muscles work. Most of the sodium in the body (about 85%) is found in blood and lymph fluid.

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3 years ago