Why does burning coal produce more heat energy than burning paper

the molar solubility of Zn(OH)2 is 5.7x 10^-3 mol/L at a certain temperature. Calculate the value of Ksp for Zn(OH)2 at this tem

Alex

Answer:

Ksp = 7.4x10⁻⁷

Explanation:

Molar solubility of a substance is defined as the amount of moles of that can be dissolved per liter of solution.

Ksp of Zn(OH)₂ is:

Zn(OH)₂(s) ⇄ Zn²⁺ + 2OH⁻

Ksp = [Zn²⁺] [OH⁻]²

And the molar solubility, X, is:

Zn(OH)₂(s) ⇄ Zn²⁺ + 2OH⁻

⇄ X + 2X

<em>Because X are moles of substance dissolved.</em>

<em>Ksp = </em>[X] [2X]²

Ksp = 4X³

As molar solubility, X, is 5.7x10⁻³mol/L:

Ksp = 4X³

Ksp = 4 (5.7x10⁻³mol/L)³

5 0

3 years ago

Sodium hydride reacts with excess water to produce aqueous sodium hydroxide and hydrogen gas:NaH (s) H2O (l) → NaOH (aq) H2 (g)A

Anuta_ua [19.1K]

NaH(s)+ H2O (l)=>NaOH(aq)+H2(g)

You want to calculate the mass of NaH, I assume. Otherwise, the question isn't clear. It simply says calculate the mass(??)

So, calculate the moles of H2 gas that satisfy the conditions of 982 ml at 28ºC and 765 torr. But you must subtract the vapor pressure of water at 28º to get the actual pressure of the H2 gas. So, the actual conditions are 982 ml (0.982 L) and 301 K and 765-28 = 737 torr.

PV = nRT

n = PV/RT = (737 torr)(0.982 L)/(62.4 L-torr/Kmol)(301 K)

n = 0.0385 moles H2

moles NaH needed = 0.0385 moles H2 x 1 mole NaH/mole H2 = 0.0385 moles NaH required

mass of NaH needed = 0.0385 moles x 24 g/mole = 0.925 g NaH

Brainliest Please :)

7 0

4 years ago

Read 2 more answers

2. Explain how conduction, convection and radiation all contribute to heating the Earth's

ANTONII [103]

Answer: Conduction, radiation and convection all play a role in moving heat between Earth's surface and the atmosphere. Since air is a poor conductor, most energy transfer by conduction occurs right near Earth's surface. ... During the day, sunlight heats the ground, which in turn heats the air directly above it via conduction.

HOPE THIS HELPS

8 0

3 years ago

What is the formula for the compound dinitrogen pentoxide? n4o5 n5o4 n4o6 n5o2 n2o5?

STALIN [3.7K]

<span>N2, penta means 5, so 5 oxygens

so with that being said n205</span>

5 0

3 years ago

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Sulfur hexafluoride gas is collected at 26.0 °C in an evacuated flask with a measured volume of 35.0 L. When all the gas has bee

stepan [7]

Answer:

The mass of sulphur hexafluoride collected over water is:

MASS IS 115.28g

NUMBER OF MOLE = 0.04 mole.

Explanation:

Gas constant, R = 0.082 L atm/ mol K

Temperature =26° C = 26 + 273 K =>299 K

Pressure = 0.03 atm

Volume = 35 L

Using the ideal gas equation, we can calculate the number of moles and hence the mass from the mass, molar mass, number of mole relationship.

PV = nRT

Re-arrange by making 'n' the subject of the equation:

n = PV / RT

n = 0.03 * 35 / 0.082 * 299

n = 1.05 / 24.518

n = 0.0428

The number of moles is therefore 0.04 moles

Then we calculate the mass:

Number of moles = mass / molar mass

But before we do that, we must calculate the molar mass of the substance collected over water.

The substance is sulphur hexafluoride and has chemical formula SF6 ( S = 32, F = 19)

Molar mass of SF6 = ( 32 + 19*6)

Molar Mass = 146 g/ mol

Equate the values and then solve for the mass, we get:

Mass = number of moles * molar mass

Mass = 0.04 * 146

Mass = 115.28 g

So therefore, the mass of the sulphur hexafluoride is 115.28g and its number of moles is 0.04 mole.

5 0

3 years ago