Answer:
25.8
Explanation:
Let's write the reaction between magnesium-phosphide and potassium:
Mg3P2 + K = Mg + K3P
And now let's balance this equation:
Mg3P2+6K=3Mg+2K3P
We see that the ratio of magnesium-phosphide and potassium is 1:6, which means that for every mole of magnesium-phosphide there need to be 6 moles of potassium.
Since we have 4.3 moles of Mg3P2, there need to be 6 • 4.3 = 25.8 moles of potassium.
First, consider the steps to heat the sample from 209 K to 367K.
1) Heating in liquid state from 209 K to 239.82 K
2) Vaporaizing at 239.82 K
3) Heating in gaseous state from 239.82 K to 367 K.
Second, calculate the amount of heat required for each step.
1) Liquid heating
Ammonia = NH3 => molar mass = 14.0 g/mol + 3*1g/mol = 17g/mol
=> number of moles = 12.62 g / 17 g/mol = 0.742 mol
Heat1 = #moles * heat capacity * ΔT
Heat1 = 0.742 mol * 80.8 J/mol*K * (239.82K - 209K) = 1,847.77 J
2) Vaporization
Heat2 = # moles * H vap
Heat2 = 0.742 mol * 23.33 kJ/mol = 17.31 kJ = 17310 J
3) Vapor heating
Heat3 = #moles * heat capacity * ΔT
Heat3 = 0.742 mol * 35.06 J / (mol*K) * (367K - 239.82K) = 3,308.53 J
Third, add up the heats for every steps:
Total heat = 1,847.77 J + 17,310 J + 3,308.53 J = 22,466.3 J
Fourth, divide the total heat by the heat rate:
Time = 22,466.3 J / (6000.0 J/min) = 3.7 min
Answer: 3.7 min
___AlBr3 + ___K -> ___KBr + ___ Al
1 AlBr3 + 3K -> 3KBr + 1 Al
hope this helps............
Answer:
Answer 1: The correct answer is b. convergent continental-continental boundary.
A convergent continental-continental boundary refers to a convergent plate boundary where two continental plates meet or come together. When this happens, a forceful collision occurs, and structures like mountains start to form. The Himalaya mountain range is formed as a result of the convergence of the Indian and Eurasian continental plates.
Answer 2: The correct answer is d. convergent oceanic-oceanic boundary.
Volcanic island arcs refers to a curved line of volcanoes formed from the subduction (sinking) of one oceanic plate below another plate. Examples of volcanic island arcs include Japanese Islands and Alaskan Islands
Hopefully this will help you my friend.
