1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
mr_godi [17]
3 years ago
15

This reaction is sometimes used to inflate life rafts, weather balloons, and the like, where a simple, compact means of generati

ng H2 is desired. How many grams of CaH2 are needed to generate 12.0 L of H2 gas if the pressure of H2 is 740. torr at 19°C?
Chemistry
1 answer:
tia_tia [17]3 years ago
5 0

Answer: 10.2 grams

Explanation:

The balanced chemical reaction is :

CaH_2(s)+2H_2O(l)\rightarrow Ca(OH)_2(aq)+2H_2(g)

According to the ideal gas equation:

PV=nRT

P = Pressure of the gas = 740 torr =  0.97 atm    (760torr=1atm)

V= Volume of the gas = 12.0 L

T= Temperature of the gas = 19°C = 292 K    0^0C=273K

R= Gas constant = 0.0821 atmL/K mol

n= moles of gas

n=\frac{PV}{RT}=\frac{0.97\times 12.0}{0.0821\times 292}

n=0.48

According to stoichiometry:

2 moles of hydrogen are generated by = 1 mole of CaH_2

Thus 0.48 moles of hydrogen are generated by =\frac{1}{2}\times 0.48=0.24 moles of CaH_2

Mass of  CaH_2=moles\times {\text {Molar mass}}=0.24mol\times 42g/mol=10.2g

Thus 10.2 grams of CaH_2 are needed to generate 12.0 L of hydrogen gas if the pressure of hydrogen is 740. torr at 19°C

You might be interested in
What is our current microscopic view of this world
Fantom [35]
EVERY YEAR, NIKON <span>selects the most artful, scientifically enlightening and skillfully produced images from thousands of submissions for its </span>Small World<span> microscope photography contest. Tomorrow, another set of impressive winners will be announced for the contest’s 40th year.</span>
6 0
3 years ago
What is the atmic number of an elemts that has six protons and eight nuetrons?
cestrela7 [59]
Atomic Number-6
Mass Number-14
5 0
3 years ago
Methane (CH4) burns in oxygen to produce carbon dioxide and water. Which reaction is occurring here?
dusya [7]
It is a combustion reaction because when methane burns with oxyzen it produces carbon dioxide,water and heat and light.
8 0
3 years ago
From what materials are fossil fuels made?
Temka [501]

Answer:

It is buried combustible geologic deposits of organic materials, formed from decayed plants and animals that have been converted to crude oil, coal, natural gas, or heavy oils by exposure to heat and pressure in the earth's crust over hundreds of millions of years.

Explanation:

5 0
3 years ago
A reaction is non-spontaneous at any temperature when
slavikrds [6]

Answer:

A reaction is non-spontaneous at any temperature when the Gibbs free energy > 0.

Explanation:

There is a state function, that determines if a reaction is sponaneous or non spontaneous:

ΔG = Gibbs free energy

A reaction is non spontaneous when it does require energy to produce that reaction. It will be spontaneous, when the reaction does not require energy to be occured.

The formula is: ΔG = ΔH - T.ΔS

ΔH → Enthalpy → Energy gained or realeased as heat.

ΔH < 0 → <em>Exothermic reaction. Spontaneity is favored </em>

T  → Temperature

ΔS → Entropy →  Degree of disorder of a system.

When the system has a considered disorder ΔS > 0, disorder increases.

When the system is more ordered, ΔS < 0, disorder decreases.

The reaction will be non spontaneous if, the enthalpy is positive (endothermic reaction) and the ΔS < 0 (disorder decreases). It will not occur if we do not give energy.

ΔG < 0 → Spontaneous reaction

ΔG > 0 → Non spontaneous reaction

ΔG = 0 → System in equilibrium

8 0
3 years ago
Other questions:
  • Select the statements that best describe the properties of an intramolecular sn2 reaction mechanism.
    7·1 answer
  • What did the professer use a catalyst for the flubber experiment
    9·1 answer
  • a scientists finds an organism that cannot move. it has many cells, produces spores, and gets food from its environment. in whic
    11·1 answer
  • Addition reactions of alkenes are characterized by _________. A) formation of a bond B) addition of two groups across a double b
    11·1 answer
  • Think about what you know about science today. How do you think scientific knowledge will be different in 100 years?
    11·1 answer
  • assume you have a 500 g sample of a radioactive isotope with a half-life of 100 years. fill in the table showing how many grams
    8·2 answers
  • Biochemistry which studies the chemical composition, structure, and the reaction of compounds found in non-living organisms.
    12·1 answer
  • Perform the following mathematical operation and then report the answer.
    8·1 answer
  • Block A is made of copper, which has a specific heat value of 0.385 J/g*C.
    13·1 answer
  • Classify the following aqueous solutions as: strong acid, weak acid, neutral, weak base, or strong base.
    10·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!