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Viefleur [7K]
3 years ago
8

Sometimes in lab we collect the gas formed by a chemical reaction over water (see sketch at right). This makes it easy to isolat

e and measure the amount of gas produced. Wala Suppose the H, gas evolved by a certain chemical reaction taking place at 40.0 °C is collected over water, using an apparatus something like that in the sketch, and the final volume of gas in the collection tube is measured to be 80.0 mL. Sketch of a gas-collection apparatus.
Calculate the mass of H, that is in the collection tube. Round your answer to 2 significant digits. You can make any normal and reasonable assumption about the reaction conditions and the nature of the gases. XS ?
Chemistry
1 answer:
ad-work [718]3 years ago
7 0

Answer:

The correct answer is 0.00582 grams.

Explanation:

In order to solve the question, let us consider the vapor pressure of H2O, as hydrogen gas is collected over water, therefore, we have to consider the vapor pressure of water in the given case. Let us assume that the pressure is 760 torr or 1 atm.

It is known that the vapor pressure of water at 40 degree C is 53.365 torr (Based on the data).

Therefore, the pressure of H2 will be,

P = 760-55.365 = 704.635 torr or 704.635/760 = 0.9272 atm

The volume of the hydrogen gas collected in the tube is 80 ml or 0.08 L

Temperature in Kelvin will be 40+273 = 313 K

To calculate the moles of hydrogen (H2) gas, there is a need to use the ideal gas equation, that is, PV= nRT, in this R is the gas constant, whose value is 0.0821 L atm/molK, and n is the moles of the gas.

By inserting the values in the equation we get:

PV = nRT

n = PV/RT = 0.9272 *0.08 / 0.0821 * 313

n = 0.00289 moles

The mass of H2 will be moles * molar mass = 0.00289 * 2.016

= 0.00582 grams.

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n-Butane (C4H10) is burned with stoichiometric amount of oxygen. Determine the mole fraction of carbon dioxide and water in the
Fudgin [204]

Answer:

See details below

Explanation:

The balanced reaction equation is given below:

2C_{4} H_{10} + 13O_{2} → 8CO_{2} + 10H_{2} O

Mole fraction of CO2 to H20

= 8/10 = \frac{4}{5}

Mole ratio of C4H10 to CO2 is 2:8 = 1:4

1 mole of n-butane - 38.12 g

4 moles - ?

= 152.48g fuel consumed.

8 0
3 years ago
How many kilojoules of energy would be required to heat a 225g block of aluminum from 23.0 C to 73.5 C?
gulaghasi [49]

Answer:

\boxed {\boxed {\sf 10.2 \ kJ}}

Explanation:

We are asked to find how many kilojoules of energy would be required to heat a block of aluminum.

We will use the following formula to calculate heat energy.

q=mc \Delta T

The mass (m) of the aluminum block is 225 grams and the specific heat (c) is 0.897 Joules per gram degree Celsius. The change in temperature (ΔT) is the difference between the final temperature and the initial temperature.

  • ΔT = final temperature - inital temperature

The aluminum block was heated from 23.0 °C to 73.5 °C.

  • ΔT= 73.5 °C - 23.0 °C = 50.5 °C

Now we know all three variables and can substitute them into the formula.

  • m= 225 g
  • c= 0.897 J/g° C
  • ΔT= 50.5 °C

q= (225 \ g )(0.897 \ J/g \textdegree C)(50.5 \textdegree C)

Multiply the first two numbers. The units of grams cancel.

q= (225 \ g  * 0.897 \ J/g \textdegree C)(50.5 \textdegree C)

q= (225   * 0.897 \ J / \textdegree C)(50.5 \textdegree C)

q= (201.825\ J / \textdegree C)(50.5 \textdegree C)

Multiply again. This time, the units of degrees Celsius cancel.

q= 201.825 \ J * 50.5

q= 10192.1625 \ J

The answer asks for the energy in kilojoules, so we must convert our answer. Remember that 1 kilojoule contains 1000 joules.

\frac { 1  \ kJ}{ 1000 \ J}

Multiply by the answer we found in Joules.

10192.1625 \ J * \frac{ 1 \ kJ}{ 1000 \ J}

10192.1625  * \frac{ 1 \ kJ}{ 1000 }

\frac {10192. 1625}{1000} \ kJ

10.1921625 \ kJ

The original values of mass, temperature, and specific heat all have 3 significant figures, so our answer must have the same. For the number we found, that is the tneths place. The 9 in the hundredth place tells us to round the 1 up to a 2.

10.2 \ kJ

Approximately <u>10.2 kilojoules</u> of energy would be required.

3 0
3 years ago
In the rock cycle, which rock type may be weathered to become sediment, and eventually sedimentary rock?
iragen [17]

i think it is I. and III.

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6 0
2 years ago
Read 2 more answers
A) if each substance above is heated at the same rate and same mass, which of the above has a smaller specific heat? how do you
aliya0001 [1]

Answer:

I think B would be alcohol but A I'm not to sure

5 0
3 years ago
Why sunlight is an essential source of life sustenance on Earth ?​
Elenna [48]

Answer:

The sun is important to Earth because it helps regulate the climate, is the main source of energy for producers in the ecosystems and it keeps the oceans from freezing, along with providing light. If just one of these factors changed dramatically, it would impact all life on Earth. Without the sun, the planet’s oceans would freeze, temperatures would drop and all life would die off without light or food.

The sun is important to every single aspect of life on the planet. Human life could not exist without it because it would cause all of the water and food sources to cease to exist. The sun is in no danger of disappearing any time soon. Scientists estimate the sun has at least another 5 billion years before it turns into a red giant and swallows up Mercury and Venus. It will also destroy all life on Earth because it will be close to the planet once that change occurs. The temperature of the sun will also increase tenfold from 18 million to 180 million degrees Fahrenheit. The increase in the sun’s size when it finally begins to change will be due to the heat increase causing expansion.

Without the sun, we would no energy to live, no plants to eat, no trees to give us oxygen or animals to roam. We would not have gravity to keep the earth in orbit. Without the sun, the earth would be dark and cold and life would quickly disappear.

7 0
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