How many formula units make up 25.8g of magnesium chloride (MgCl2)? Express the number of formula units numerically.

What is the ph of 0.20 m nitrous acid at equilibrium (ka= 4.6×10-4)?

Alex787 [66]

Nitrous acid is HNO2. Its dissociation is HNO2 = H(+) + NO2(-). The equilibrium constant, Ka = [H+][NO2-]/[HNO2] => x^2 / (0.20 - x). Given that it is a weak acid (Ka = 4.6 * 10^ -4),you can use a very good approxiamation: 0.20 >> x => 0.20 - x = 0.20, and this permits you to solve the value of x more easily. => 4.6 * 10^-4 = (x^2) / 0.20 => x^2 = 0.20 * 4.6 * 10^ -4 = 0.92 * 10^-4 => x = 9.59 * 10^ -3. Now,calculate pH = log { 1 / [H+] } = log { 1 / (9.59 * 10 ^-3) } = 2.02. <span>Answer pH = 2.02</span>

6 0

3 years ago

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Bohr model worksheet

cluponka [151]

What’s the question?

3 0

4 years ago

How many grams hydrogen in 4.5 mol H2SO4

swat32

H2SO4 ---> 2H^+ + SO4^2-

Hence n H+ = 9 mols

Mass of H = nM = (9*1) = 9g

Alternately

mass of H2SO4= nM= 4.5*98= 441

Mass of H= mass h2so4 * molar mass of H/molar mass of h2so4
Mass of H= 441 * 2/98 = 9g

4 0

3 years ago

Which property describes the shininess of an element?

goldenfox [79]

Answer: Metals are shiny and lustrous with a high density. They have very high melting and boiling points because metallic bonding is very strong, so the atoms are reluctant to break apart into a liquid or gas.

Explanation:

sorry for not answering in less than 1 minute

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3 years ago

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The coefficient of thermal expansion α = (1/V)(∂V/∂T)p. Using the equation of state, compute the value of α for an ideal gas. Th

andreyandreev [35.5K]

Answer:

The coefficient of thermal expansion α is

$\alpha = \frac{1}{T}$