Answer:
A) The atoms of the reactants unbond, rearrange and then rebond to form the products
Explanation:
Using method of elimination:
A) The atoms of the reactants unbond, rearrange and then rebond to form the products
This is the correct option. Chemical reactions involves breaking and forming of new bonds.
B) Some atoms disappear while others multiply to form the products
This option is incorrect. Atoms do not disappear
C) The atoms of the reactants always stay together to form the products
This option is incorrect. The bonds between the atoms in the reactants must first be broken before products can be formed.
D) New atoms are formed which combine to make the products
This option is incorrect. Atoms do not just form out of nowhere.
Answer:
Mass = 65.8 g
Explanation:
Given data:
Mass of sodium chloride = ?
Volume of solution = 1.5 L
Molarity of solution = 0.75 M
Solution:
Number of moles of sodium chloride:
Molarity = number of moles / volume in L
By putting values,
0.75 M = number of moles = 1.5 L
Number of moles = 0.75 M × 1.5 L
Number of moles = 1.125 mol
Mass of sodium chloride:
Mass = number of moles × molar mass
Mass = 1.125 mol × 58.5 g/mol
Mass = 65.8 g
Both carbon and lead belong to Group IV elements, and thus they have the same number of valence electrons.
<span>In each of the other options, the two elements belong to different groups, and thus they do NOT have the same number of valence electrons.</span>
Missing question: What is the vapor pressure of the solution at 25°<span>C?
n(NaCl) = 100 g </span>÷ 58,4 g/mol.
n(NaCl) = 1,71 mol.
NaCl → Na⁺ + Cl⁻, amount of ions are 2 · 1,71 mol = 3,42 mol.
n(CaCl₂) = 100 g ÷ 111 g/mol = 0,9 mol.
CaCl₂ → Ca²⁺ + 2Cl⁻, amount of ions 3 · 0,9 mol = 2,7 mol.
m(solution) = 1000 ml (1,00 L) · 1,15 g/ml = 1150 g.
m(H₂O) = 1150 g - 100 g - 100 g = 950 g.
n(H₂O) = 950 g ÷ 18 g/mol = 118,75 mol.
<span>water's mole fraction = 118,75 mol </span>÷ (118,75 mol + 2,7 mol + 3,42 mol).
water's mole fraction = 0,95.
p(solution) = 0,95 · 23 mmHg = 21,85 mmHg.