The answer is:
a. 0.712 M
b. 0.210 M
c. 0.336 M
Molarity is a measure of the concentration of solute in a solution.
It can be expressed as moles of solute ÷ volume of solution:
c = n ÷V
where:
c - concentration of solute,
n - moles of solute
V - volume of solution
n can be expressed as:
<span>n = m ÷ Mr
</span>where:
<span>n - moles of solute
</span>m - mass of solute
Mr - relative molecular mass
a. We know volume:
V = 289.2 mL = 0.2892 L
We need n and c.
n = m ÷ Mr
m = 15.4 g
Mr (<span>KCl) = 74.55 g/mol
n = </span>15.4 g ÷ <span>74.55 g/mol
n = 0.206 mol</span>
Thus,
c = 0.206 mol ÷ <span>0.2892 L
c = 0.712 mol/L = 0.712 M
</span>b. We know volume:
V = 0.614 L
We need n and c.
n = m ÷ Mr
m = 14.4 g
Mr (CaCl₂<span>) = 110.98 g/mol
n = </span>14.4 g ÷ <span>110.98 g/mol
n = 0.129 mol</span>
Thus,
c = 0.129 mol ÷ <span>0.614 L
c = 0.210 mol/L = 0.210 M
</span>
c. We can use formula:
m₁V₁ = m₂V₂
<span>m₁ = 3 M
</span><span>V₁ = 28 mL= 0.028 L
</span><span>m₂ = ?
</span><span>V₂ = 0.250 L
</span>Thus:
3 M × 0.028 L = m₂× <span>0.250 L
</span> m₂ = 0.336 M
Answer:I believe the correct answer from the choices listed above is option D. A
Explanation:neutral atom possesses an atomic number of 15 and an atomic mass of 31.Three electrons are gained. This conversion results to a negatively charged ion.
Answer:
The reaction is spontaneous when T > 2170 K.
Explanation:
The spontaneity of a reaction is related to the standard Gibbs free energy (ΔG°). When ΔG° < 0 the reaction is spontaneous. ΔG° is related to the standard enthalpy (ΔH°) and the standard entropy (ΔS°) through the following expression:
ΔG° = ΔH° - T.ΔS°
where,
T is the absolute temperature
The reaction is spontaneous when ΔG° < 0, that is,
ΔH° - T.ΔS° < 0
ΔH° < T.ΔS°
T > ΔH°/ΔS° = (169.4 × 10³ J)/(78.1 J/K) = 2170 K
The reaction is spontaneous when T > 2170 K.
Answer:
Six atoms of calcium, four of phosphorous and sixteen of oxygen for a total of twenty six
Explanation:
Hello there!
In this case, according to the molecular formula of the two moles of calcium phosphate:
Thus, in order to calculate the atoms of each atom, it is necessary to multiply the two in front of the formula by the subscripts in the reaction:
Thus, we obtain six atoms of calcium, four of phosphorous and sixteen of oxygen for a total of twenty six.
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