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3 years ago

If you pump air into cycle tyre a slight warming effect is noticed at valve stem why

1 answer:

8 0

Probably the kinetic energy of rubbing the pump against the valve, combined with the increase in gas pressure in the tire itself.

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Mrs. Lewis gives you a piece of iron and asks you to determine the physical and chemical properties of the metal. She wants you

Andreyy89

A. Identify the properties as either a physical or chemical property. (first 3 are chemical, last is physical)

7 0

3 years ago

When a gas is heated, the gas particles have more kinetic energy. Complete the following sentence: This means they move about mo

Volgvan

Answer:

Contact

Explanation:

As the speed of the particles increases, they move around more, which means they hit the sides of the container more.

3 0

3 years ago

CH4 with pressure 1 atm and volume 10 liter at 27°C is passed into a reactor with 20% excess oxygen, how many moles of oxygen is

BaLLatris [955]

Answer : The moles of $O_2$ left in the products are 0.16 moles.

Explanation :

First we have to calculate the moles of $CH_4$ .

Using ideal gas equation:

$PV=nRT$

where,

P = pressure of gas = 1 atm

V = volume of gas = 10 L

T = temperature of gas = $27^oC=273+27=300K$

n = number of moles of gas = ?

R = gas constant = 0.0821 L.atm/mol.K

Now put all the given values in the ideal gas equation, we get:

$(1atm)\times (10L)=n\times (0.0821L.atm/mol.K)\times (300K)$

$n=0.406mole$

Now we have to calculate the moles of $O_2$ .

The balanced chemical reaction will be:

$CH_4+2O_2\rightarrow CO_2+2H_2O$

From the balanced reaction we conclude that,

As, 1 mole of $CH_4$ react with 2 moles of $O_2$

So, 0.406 mole of $CH_4$ react with $2\times 0.406=0.812$ moles of $O_2$

Now we have to calculate the excess moles of $O_2$ .

$O_2$ is 20 % excess. That means,

Excess moles of $O_2$ = $\frac{(100 + 20)}{100}$ × Required moles of $O_2$

Excess moles of $O_2$ = 1.2 × Required moles of $O_2$

Excess moles of $O_2$ = 1.2 × 0.812 = 0.97 mole

Now we have to calculate the moles of $O_2$ left in the products.

Moles of $O_2$ left in the products = Excess moles of $O_2$ - Required moles of $O_2$

Moles of $O_2$ left in the products = 0.97 - 0.812 = 0.16 mole

Therefore, the moles of $O_2$ left in the products are 0.16 moles.

7 0

3 years ago

Classify each of the following properties as physical or chemical: A. Ice melts in the sun. B. Copper is a shiny metal. C. Paper

vampirchik [111]

Answer:

The answer to your question is below

Explanation:

Physical properties are the properties in which there is no change in the nature of the substance but there is a change in the physical state.

Chemical properties are the properties in which the substance changes its nature. A new substance is formed.

A. Ice melts in the sun. Physical p.

B. Copper is a shiny metal. Physical p.

C. Paper can burn. Chemical p.

D. A silver knife can tarnish. Physical p.

E. A magnet removes iron particles from a mixture. Physical p.

8 0

3 years ago

Electron A falls from energy level X to energy level Y and releases blue light. Electron B falls from energy level Y to energy l

MrMuchimi

Answer: Transition from X to Y will have greater energy difference.

Explanation: For studying the energy difference, we require Planck's equation.

$E=\frac{hc}{\lambda}$

where, h = Planck's Constant

c = Speed of light

E = Energy

$\lambda$ = Wavelength of particle

From the equation, it is visible that the energy and wavelength follow inverse relation which means that with low wavelength value, energy will be the highest and vice-versa.

As electron A falls from X-energy level to Y-energy level, it releases blue light which has low wavelength value (around 470 nm) which means that it has high energy.

Similarly, Electron B releases red light when it falls from Y-energy level to Z-energy level, which has high wavelength value (around 700 nm), giving it a low energy value.

Energy Difference between X-energy level and Y-energy level will be more.

5 0

3 years ago