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Wittaler [7]
3 years ago
14

Calcium hydride (cah2) reacts with water to form hydrogen gas: cah2(s) + 2h2o(l) → ca(oh)2(aq) + 2h2(g) how many grams of cah2 a

re needed to generate 58.0 l of h2 gas at a pressure of 0.811 atm and a temperature of 32°c?
Chemistry
1 answer:
andreev551 [17]3 years ago
3 0
Using the ideal gas law equation, we can find the number of H₂ moles produced.
PV = nRT
Where P - pressure - 0.811 atm x 101 325 Pa/atm = 82 175 Pa
V - volume - 58.0 x 10⁻³ m³
R - universal gas constant - 8.314 Jmol⁻¹K⁻¹
T - temperature - 32 °C + 273 = 305 K
substituting these values in the equation,
82 175 Pa x 58.0 x 10⁻³ m³ = n x 8.314 Jmol⁻¹K⁻¹ x 305 K
n = 1.88 mol 

The balanced equation for the reaction is as follows;
CaH₂(s) + 2H₂O(l) --> Ca(OH)₂(aq) + 2H₂(g)
stoichiometry of CaH₂ to H₂ is 1:2
When 1.88 mol of H₂ is formed , number of CaH₂ moles reacted = 1.88/2 mol
therefore number of CaH₂ moles reacted = 0.94 mol
Mass of CaH₂ reacted - 0.94 mol x 42 g/mol  = 39.48 g of CaH₂ are needed
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The equation shown represents cellular respiration. Glucose + X → Y + Water + Energy What do X and Y most likely represent? X re
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Answer:

X represents oxygen and Y represents carbon dioxide.

Explanation:

Because in respiration, you consume oxygen and make carbon dioxide whereas, in photosynthesis, the equation is reversed and you use carbon dioxide and make oxygen and glucose.

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3 years ago
Which element is a metal that is in the liquid phase at STP?
antoniya [11.8K]
I think the answer is mercury
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3 years ago
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Espresso Coffee House is designing a coffee mug that keeps liquids hot. The research department tested several different materia
raketka [301]

Answer:

This question is incomplete

Explanation:

This question is incomplete because the result of the described experiment would have better determined the type of scientific explanation to profer. However, the type of material that will preserve the relative hotness or temperature of the hot coffee for the longest time will be a material than can resist heat transfer. These materials tend to keep hot substances hot by not allowing the heat of the coffee to be conducted or pass through it. These materials are mostly insulators or made by placing an insulator between two heat conductors.

Generally, heat is usually transferred from a region of higher concentration to a region of lower concentration, hence when the heat is denied of this transfer, the heat will remain trapped in the "heat-donor" substance (in this case the hot coffee). Thus, the material chosen (A, B or C) will be the material that resists heat transfer the most based on the explanation above.

4 0
3 years ago
A certain metal M forms a soluble sulfate salt MSO, Suppose the left half cell of a galvanic cell apparatus is filled with a 3.0
dimaraw [331]

Explanation:

It is known that for high concentration of M^{2+}, reduction will take place. As, cathode has a positive charge and it will be placed on left hand side.

Now, E^{o}_{cell} = 0 and the general reaction equation is as follows.

         M^{2+} + M \rightarrow M + M^{2+}

                3.00 M        n = 2       30 mM

         E = 0 - \frac{0.0591}{2} log \frac{50 \times 10^{-3}}{1}

            = -\frac{0.0591}{2} log (5 \times 10^{-2})

            = 0.038 V

Therefore, we can conclude that voltage shown by the voltmeter is 0.038 V.

5 0
3 years ago
4. Consider the following data: Metal Mass (9 Cu Specilic Heat_Wg % Temperature, 0,900 0.285 these two metals are placed in cont
lana66690 [7]

The heat will flow from copper to aluminum because Cu is at higher temperature. The heat liberated is -7.60kJ

When two metals at different temperatures are kept in contact, heat flows from hotter metal to colder metal until thermal equilibrium is reached.

Here Copper is at a temperature of 60 degree Celsius and aluminum is at 40 degree Celsius. Thus, heat will flow from Cu to Al.

In order to calculate the amount of heat liberated following calculations are required.

m1=262 g

T1=87 oC

Cp=0.385 J/g oC

T2=11.8 oC

The heat liberated can be expressed as follows:

Q=mCp(T2-T1)

Q=262 g*0.385 J/goC(11.8-87)oC

Q=-7585 J

=-7.60kJ

To learn more about heat check the link below:

brainly.com/question/13439286

#SPJ4

4 0
1 year ago
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