Hello,
Here is your answer:
The proper answer to this question is option D "wood is burned". Its a chemical change because its changing forms wood to ash.
Your answer is D.
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x21 +ANSWER
(i) Ne-22
(ii)1s2s22p6
(iii)21.3
An element X exists in three forms A, B and C in the ratio 1:2:3. If C has 10 protons and the number of neutrons in A, B and C are 10, 11 and 12 respectively,Give the following:(i) Representation of form C of the element X(ii) Electronic configuration of form B of the element(iii) Calculate the average atomic mass.
(i)C has 10 protons and 12 neutrons so a mass of 10 +12 =22
element 10 is Neon (Ne) so this isotope is Ne-22
(ii) they all have the sane atomic number so the same number of electrons
with an electronic structure of 1s2s22p6
(iii) A weighs 20, B weighs 21, C weighs 22
the ratio is 1:2:3
weighted average weight is therefor
(1X20 +2X21 +3X22)/6 =21.3
Air has mass and density, and. cold air is denser than warm air.
The same amount of water as oil air
Answer is: <span>yield of a reaction is 56,4%.
</span>Chemical reaction: PCl₃ + 3H₂O → 3HCl + H₃PO₃.
m(PCl₃) = 200 g.
m(HCl) = 91,0 g.
n(PCl₃) = m(PCl₃) ÷ M(PCl₃).
n(PCl₃) = 200 g ÷ 137,33 g/mol.
n(PCl₃) = 1,46 mol.
n(HCl) = m(HCl) ÷ M(HCl).
n(HCl) = 91 g ÷ 36,45 g/mol.
n(HCl) = 2,47 mol.
From reaction: n(PCl₃) : n(HCl) = 1 : 3.
n(HCl) = 1,46 mol · 3 = 4,38 mol.
Yield of reaction: 2,47 mol ÷ 4,38 mol · 100% = 56,4%.
