Help it’s due at a certain time

Is making salt water to gurgle for a sore throat a physical or chemical change

Rus_ich [418]

The answer is Physical Change.

4 0

4 years ago

What is the OH in a solution made by adding 0.060 mole of calcium oxide to 500.0ml

Alex73 [517]

Answer:

0.24 mol/L.

Explanation:

Ca(OH)₂ dissociates in solution according to the equation:

Ca(OH)₂ → Ca²⁺ + 2OH⁻.

Every 1.0 mol of Ca(OH)₂ dissociates to give 2.0 moles of OH⁻.

∴ The no. of moles of OH⁻ produced from 0.06 mol of Ca(OH)₂ = (2 x 0.06 mol) = 0.12 mol.

∴ [OH⁻] = no. of moles / V of the solution = (0.12 mol)/(0.5 L) = 0.24 mol/L.

8 0

4 years ago

Magicians often use ‘flash powder’ in their acts. Flash powder contains 69.0% potassium chlorate (31.9% K, 28.9% Cl, 39.2% O) an

mafiozo [28]

Answer:

$\rm K$ : approximately $22.0\%$ .

$\rm Cl$ : approximately $19.9\%$ .

$\rm O$ : approximately $27.0\%$ .

$\rm Al$ : $31.0\%$ .

Explanation:

Consider a $100\; \rm g$ sample. There would be $69.0\% \times 100\; \rm g = 69.0\; \rm g$ of $\rm KClO_{3}$ and $100.0\; \rm g - 69.0\; \rm g = 31.0\; \rm g$ of $\rm Al$ .

Out of that $69.0\; \rm g$ of $\rm KClO_{3}$ :

$31.9\%$ (by mass) would be $\rm K$ : $31.9\% \times 69.0\; \rm g \approx 22.0\; \rm g$ .

$28.9\%$ (by mass) would be $\rm Cl$ : $28.9\% \times 69.0\; \rm g \approx 19.9\; \rm g$ .

$39.2\%$ (by mass) would be $\rm O$ : $39.2\% \times 69.0\; \rm g \approx 27.0\; \rm g$ .

Overall, the composition (by mass) of each element in this mixture would be:

$\rm K$ :

$\begin{aligned} & \frac{31.9\% \times 69.0\; \rm g}{100\; \rm g} \\ =\; & 31.9\% \times 69.0\% \\ \approx \; & 22.0\%\end{aligned}$ .

$\rm Cl$ :

$\begin{aligned} & \frac{28.9\% \times 69.0\; \rm g}{100\; \rm g} \\ =\; & 28.9\% \times 69.0\% \\ \approx \; & 19.9\%\end{aligned}$ .

$\rm O$ :

$\begin{aligned} & \frac{39.2\% \times 69.0\; \rm g}{100\; \rm g} \\ =\; & 39.2\% \times 69.0\% \\ \approx \; & 27.0\%\end{aligned}$ .

$\rm Al$ :

$\begin{aligned}& \frac{100\; \rm g - 69.0\; \rm g}{100\; \rm g} \\ =\; & 100\% - 69.0\% \\ =\; & 31.0\%\end{aligned}$ .

7 0

3 years ago

Use ksp=4.87×10−17 to calculate the solubility of iron (ii) hydroxide in pure water in grams per 100.0 ml of solution. g

marysya [2.9K]

The ksp = 4.87 × 10^-17
Therefore; 4.87 ×10^-17 = [Fe2+][OH-]^2 = (X)(2X)^2 = 4X^3
Hence;
4x^3 =4.87 × 10^-17
x = 2.30 × 10^-6 M
therefore the molarity is 2.3 ×10^-6 M
Thus;
The mass of Fe(OH)2 in 100 ml of water, will be given by:
= 2.30 × 10^-6 mol/L = 2.3 ×× 10^-5 mole/100 mL
= 89.86 g/mol × 2.3 × 10^-6 × 0.100 = 2.07 × 10^-5 g
= 2.07 × 10^-5 g
= 2.07 × 10^-5 g

5 0

3 years ago

Phosphorus tribromide decomposes to form phosphorus and bromide, like this:

kenny6666 [7]

Answer:

Kp = 9.3x10⁴

Explanation:

The reaction is this:

4PBr₃ (g) ⇄ P₄ (g) + 6Br₂ (g)

We define Kp from the partial pressures in equilibrium

PBr₃ → 97.4 atm

P₄ → 99.2 atm

Br₂ → 97.2 atm

Kp = (Partial pressure Br₂)⁶ . (Partial pressure P₄) / (Partial pressure PBr₃)⁴

Kp = 97.2⁶ . 99.2 / 97.4⁴

Kp = 929551.4533

929551.4533 → 9.3x10⁴

4 0

3 years ago