The original sample of potassium phosphate octahydrate had a mass of 19.6 grams. When it was heated, it released 7.93 grams of water.
Further Explanation:
For every mole of the compound potassium phosphate octahydrate, there are 8 moles of water of hydration which can be removed from the crystal by heating without altering the chemical composition of the substance.
To determine how much original sample was used, the amount of water released upon heating may be used as well as the mole ratio of the water of hydration with the compound itself following the steps below:
- Convert mass of water released to moles.
- Use the mole ratio of water of hydration to the compound (8 mol water for every mol of potassium phosphate octahydrate) to get the moles of original sample.
- Convert the moles of original sample to grams.
STEP 1: Convert 7.93 g water to moles.

STEP 2: Calculate the moles of original sample using the mole ratio: 1 mol K3PO4 8H2O : 8 mol H2O.

STEP 3: Convert the moles of original sample to mass.

Following the significant figures of the given, the final answer should be:

Learn More:
- Learn more about water of hydration brainly.com/question/6053815
- Learn more about mole conversion brainly.com/question/12979299
- Learn more about percent hydrate brainly.com/question/12398621
Keywords: water of hydration, hydrate
The chemical reaction would be:
<span>2nh3(g) + h2so4(aq) = (nh4)2so4(aq)
</span>
To determine the ammonia needed, we use the given amount of the product to be produced and use the chemical equation to relate the substances. We do as follows:
3.60 × 105 kg (nh4)2so4 ( 1 kmol / 132.14 kg ) ( 2 kmol NH3 / 1 kmol (nh4)2so4 ) (17.04 kg / 1 kmol ) = 92846.98 kg NH3 needed
Answer:
a) 7.96* 10⁻³ s
b) 0.0112 s
c) 1.645* 10⁻³⁸ g
Explanation:
for the reaction
Cyclobutane (A) → 2 ethylene (B)
the reaction rate (first order )is
-dCa/dt = k*Ca
∫dCa/Ca = - ∫k*dt
ln(Ca/Ca₀) = -k*t → Ca = Ca₀*e^(-k*t)
therefore
a) the half- life represents the time required for the concentration Ca to drop to half of the initial value ( Ca=Ca₀/2) therefore
Ca₀/2 = Ca₀*e^(-k*t) → - ln 2 = -k*t → t = ln 2 / k =ln 2 / ( 87 1/s) = 7.96* 10⁻³ s
b) Ca = Ca₀*e^(-k*t) , for Ca= Wa/(V*M) , where Wa is weight:
Wa = Wa₀*e^(-k*t)
for Wa₀= 4 g and Wa = 4g - 2.5 g = 1.5 g
→ t= (1/k)* ln(Wa₀/Wa) = 1/( 87 1/s) * ln [ 4g/(1.5 g)] = 0.0112 s
c) for Wa₀= 4 g and t=1 s
Wa = Wa₀*e^(-k*t) = 1 g * e^(- 87 (1/s) *1 s )= 1.645* 10⁻³⁸ g ≈ 0