Answer:
1) D; 2) B
Explanation:
1) <em>Conservation of atoms
</em>
D is correct.
It has four atoms of H and two of O on each side of the reaction arrow.
A. <em>Wrong</em>. It has the same number of H and O on each side, but it has the <em>wrong product</em>. The reaction forms O₂ molecules, not O atoms.
B. <em>Wrong</em>. Atoms are balanced, but the <em>products are incorrect</em>.
C. <em>Wrong</em>. Atoms are balanced, but the <em>reactants are incorrect</em>.
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2) <em>Chemical equations
</em>
B is correct.
The atoms are balanced, and the equation shows the correct formulas of the molecules.
A. <em>Wrong</em>. Atoms are balanced, and the formulas are correct, but the equation is <em>not in its simplest form</em>. The coefficients are not in their lowest terms. We must divide every coefficient by six to get the correct equation: H₂ + Cl₂ ⟶ 2HCl.
C. <em>Wrong</em>. The <em>reactants are incorrect</em>, and the equation is <em>not in its lowest terms</em>.
D. <em>Wrong</em>. The <em>reactants are incorrect</em>.
How did you post this pic?
Oxygen is gas. It has 2 O atoms. Atomic mass of 1 O atom is 16 amu. So molecular mass of O2 = 2 x 16 = 32 amu.
Now, mass of 6.023 x 10 ^23 = 32 amu.
Therefore mass of 3.01 x 10^23 = 32 x 3.01 x 10^23 / 6.023 x 10 ^23 = 15.99
= ~16 gm
