The mass percent of hydrogen in CH₄O is 12.5%.
<h3>What is the mass percent?</h3>
Mass percent is the mass of the element divided by the mass of the compound or solute.
- Step 1: Calculate the mass of the compound.
mCH₄O = 1 mC + 4 mH + 1 mO = 1 (12.01 amu) + 4 (1.00 amu) + 1 (16.00 amu) = 32.01 amu
- Step 2: Calculate the mass of hydrogen in the compound.
mH in mCH₄O = 4 mH = 4 (1.00 amu) = 4.00 amu
- Step 3: Calculate the mass percent of hydrogen in the compound.
%H = (mH in mCH₄O / mCH₄O) × 100%
%H = 4.00 amu / 32.01 amu × 100% = 12.5%
The mass percent of hydrogen in CH₄O is 12.5%.
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Answer:
only chlorine can expand its octet.
Explanation:
An atom can expand its octet is it has empty d orbital
the electronic configuration of given elements will be:
B : 1s2 2s2 2p1 [Valence shell n =2 no d orbital]
O :1s2 2s2 2p4 [Valence shell n =2 no d orbital]
F : 1s2 2s2 2p5 [Valence shell n =2 no d orbital]
Cl :1s2 2s2 2p6 3s2 3p5 3d0 [Valence shell n =2 no d orbital]
Out of given elements only chlorine has empty d orbitals in its valence shell
Thus only chlorine can expand its octet.
Answer:
1.70
Explanation:
The molar mass of perchloric acid is 100.46 g/mol. The moles corresponding to 484 mg (0.484 g) are:
0.484 g × (1 mol/100.46 g) = 4.82 × 10⁻³ mol
4.82 × 10⁻³ moles are dissolved in 240 mL (0.240 L) of solution. The molar concentration of perchloric acid is:
4.82 × 10⁻³ mol/0.240 L = 0.0201 M
Perchloric acid is a strong monoprotic acid, that is, it dissociates completely, so [H⁺] = 0.0201 M.
The pH is:
pH = -log [H⁺] = -log 0.0201 = 1.70
Nickel contains more atoms.
<u>Explanation:</u>
Number of atoms is determined by the Avogadro number.
1 mole of substance contains 6.022 X 10²³ atoms.
Given:
Mass of Nickel, Ni = 3.89g
Molecular weight of Ni = 58.6934g
Number of moles of Ni = 3.89/58.6934g
Number of atoms of Ni = 
Number of atoms of Ni = 0.39 X 10²³
Mass of silver, Ag = 6.61g
Molecular weight of Ag = 107.8682g
Number of moles of Ag = 6.61/107.8682
Number of atoms of Ag = 
Number of atoms of Ag = 0.36 X 10²³
Therefore, Nickel contains for atoms.
Answer:
32.8%
Explanation:
All of the Pb⁺² species precipitated as lead(II) cromate, PbCrO₄ (we know this as excess K₂CrO₄ was used).
First we convert 0.130 g of PbCrO₄ into moles, using its molar mass:
- 0.130 g ÷ 323 g/mol = 4.02x10⁻⁴ mol PbCrO₄
There's 1 Pb⁺² mol per PbCrO₄ mol, so in total 4.02x10⁻⁴ moles of Pb⁺² were in the ethanoate sample.
We <u>convert those 4.02x10⁻⁴ moles of Pb into grams</u>:
- 4.02x10⁻⁴ mol * 207 g/mol = 0.083 g Pb
Finally we calculate the percentage composition of Pb:
- 0.083 g Pb / 0.254 g salt * 100% = 32.8%
