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Fofino [41]
4 years ago
7

What is the percent composition of Ca(OH)2? 37.7% Ca, 53.0% O, and 10.3% H 45.5% Ca, 38.2% O, and 16.3% H 54.0% Ca, 43.0% O, and

2.7% H 64.7% Ca, 27.0% O, and 8.3% H
Chemistry
1 answer:
Naddik [55]4 years ago
6 0

The molar mass of Calcium hydroxide is 74 g/mol

To find the percent composition we have to find the number of atoms of each element in the formula .

So there’s

Calcium - 1

Oxygen - 2

Hydrogen - 2

Then have to multiply the relative atomic mass of each element by the number of atoms

Ca - 40 g/mol x 1 = 40

O - 16 g/mol x 2 = 32

H - 1 g/mol x 2 = 2

Then To find percent composition of each element we have to divide the mass of each element in the formula by the relative molecular mass of calcium hydroxide

Ca - 40 / 74 x 100 % = 54.0%

O - 32 / 74 x 100 % = 43.2 %

H - 2 / 74 x 100 % = 2.7%

From the options given correct answer is 3rd option

54.0% Ca , 43.0% O and 2.7 % H

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What types of elements- metals,
crimeas [40]

Answer:

Noble gases

Explanation:

The noble gases are non-metals that requires the highest amount of energy to remove an electron from their shells.

The reason for this difficult is that their electronic configuration confers a stable configuration them.

  • The ionization energy is the energy required to remove the most loosely held electrons in an atom.
  • Due to the special stability of noble gases, it is very difficult to remove electrons from an atom of noble gases.
7 0
3 years ago
Write the condensed ground-state electron configurations of these transition metal ions, and state which are paramagnetic:
jok3333 [9.3K]

Answer:

a) Mo the electron configuration: 42Mo: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d4

Mo3+ - is Paramagnetic

b) Au - [Xe] 4f14 5d10 6s1

For Au+ is not paramagnetic

c) Mn - [Ar] 3d5 4s2

Mn2+ is paramagnetic

d)Hf -[Xe] 4f¹⁴ 5d² 6s²

Hf2+ is not paramagnetic

Explanation:

An atom becomes positively charged when it looses an electron.

Diamagnetism in atom occurs whenever two electrons in an orbital paired equalises with a total spin of 0.

Paramagnetism in atom occurs whenever at least one orbital of an atom has a net spin of electron. That is a paramagnetic electron is just an unpaired electron in the atom.

Here is a twist even if an atom have ten diamagnetic electrons, the presence of at least one paramagnetic electron, makes it to be considered as a paramagnetic atom.

Simply put paramagnetic elements are one that have unpaired electrons, whereas diamagnetic elements do have paired electron.

3 0
3 years ago
Please review the attachment
astra-53 [7]

Answer: The correct answer is -297 kJ.

Explanation:

To solve this problem, we want to modify each of the equations given to get the equation at the bottom of the photo. To do this, we realize that we need SO2 on the right side of the equation (as a product). This lets us know that we must reverse the first equation. This gives us:

2SO3 —> O2 + 2SO2 (196 kJ)

Remember that we take the opposite of the enthalpy change (reverse the sign) when we reverse the equation.

Now, both equations have double the coefficients that we would like (for example, there is 2S in the second equation when we need only S). This means we should multiply each equation (and their enthalpy changes) by 1/2. This gives us:

SO3 —>1/2O2 + SO2 (98 kJ)

S + 3/2O2 —> SO3 (-395 kJ)

Now, we add the two equations together. Notice that the SO3 in the reactants in the first equation and the SO3 in the products of the second equation cancel. Also note that O2 is present on both sides of the equation, so we must subtract 3/2 - 1/2, giving us a net 1O2 on the left side of the equation.

S + O2 —> SO2

Now, we must add the enthalpies together to get our final answer.

-395 kJ + 98 kJ = -297 kJ

Hope this helps!

8 0
3 years ago
Read 2 more answers
Formic acid, which is a component of insect venom, has a ka = 1.8 ´ 10-4. what is the [h3o+] in a solution that is initially 0.1
scoray [572]
Answer is: concentratio of H₃O⁺ ions is 4.2·10⁻³ M.<span>
Chemical reaction: HCOOH(aq) + H</span>₂O(l) ⇄ HCOO⁻(aq) + H₃O⁺(aq).<span>
c(HCOOH) = 0,1 M.
[</span>H₃O⁺] = [HCOO⁻] = x.<span>
[HCOOH] = 0,1 M - x.
</span>Ka = [H₃O⁺] · [HCOO⁻] / [HCOOH].
0,00018 = x² / (0,1 M - x).<span>
Solve quadratic equation: x = </span>[H₃O⁺] = 0,0042 M.
7 0
3 years ago
N2 + 3 H2 – 2 NH3 How many moles of nitrogen (N2) are required to get 6
Iteru [2.4K]

Answer:

N2 + 3H2 → 2NH3. 14 moles a. If 6 mol of H2 are consumed, how many moles of NH3 are produced? ... a 3 mol H₂. 4. How many moles of nitrogen are needed to make 11 moles of NH3? Il mol NH₃ x Imol Na = 15.5

5 0
3 years ago
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