<span>Chlorine has 17 electrons in it natural state but it gains an electron and becomes an anion with 18 electrons. </span>

Potassium (K) has 19 electrons in its natural state. It loses an electron and becomes K+ and then is left with 18 <span>electrons .
</span>
The atomic number of calcium is 20 i.e. Ca has 20 electrons.It Loses 2 electrons and becomes Ca++ and has 18 electrons.

7 0

4 years ago

The mole fraction of CO2 in a certain solution with H2O as the solvent is 3.6 × 10−4. What is the approximate molality of CO2 in

nataly862011 [7]

Answer: C) 0.020 m

Explanation:

Molality of a solution is defined as the number of moles of solute dissolved per kg of the solvent.

$Molality=\frac{n\times 1000}{W_s}$

where,

n = moles of solute

$W_s$ = weight of solvent in g

Mole fraction of $CO_2$ is = $3.6\times 10^{-4}$ i.e. $3.6\times 10^{-4}$ moles of $CO_2$ is present in 1 mole of solution.

Moles of solute $(CO_2)$ = $3.6\times 10^{-4}$

moles of solvent (water) = 1 - $3.6\times 10^{-4}$ = 0.99

weight of solvent = $moles\times {\text {Molar mass}}=0.99\times 18=17.82g$

Molality = $\frac{3.6\times 10^{-4}\times 1000}{17.82g}=0.020$

Thus approximate molality of $CO_2$ in this solution is 0.020 m

5 0

4 years ago

A 100g of sample of a compound is combusted in excess oxygen and the products are 2.492g of CO2 and 0.6495 of H2O. Determine the

ruslelena [56]

The empirical formula : C₁₁O₁₄O₃

<h3>Further explanation</h3>

The assumption of the compound consists of C, H, and O

mass of C in CO₂ =

$\tt \dfrac{12}{44}\times 2.492=0.680~g$

mass of H in H₂O =

$\tt \dfrac{2.1}{18}\times 0.6495=0.072~g$

mass of O :

mass sample-(mass C + mass H)

$\tt 1-(0.68+0.072)=0.248`g$

mol of C :

$\tt \dfrac{0.68}{12}=0.056$

mol of H :

$\tt \dfrac{0.072}{1}=0.072$

mol of O :

$\tt \dfrac{0.248}{16}=0.0155$

divide by 0.0155(the lowest ratio)

C : H : O ⇒

$\tt \dfrac{0.056}{0.0155}\div \dfrac{0.072}{0.0155}\div \dfrac{0.0155}{0.0155}=3.6\div 4.6\div 1\\\\\dfrac{11}{3}\div \dfrac{14}{3}\div \dfrac{3}{3}=11:14:3$

3 0

3 years ago