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2 years ago

Which sample of matter is classified as a substance

Chemistry

1 answer:

rosijanka [135]2 years ago

3 0

Answer:

Elements and Compounds. Any sample of matter that has the same physical and chemical properties throughout the sample is called a substanceAny sample of matter that has the same physical and chemical properties throughout the sample.

Explanation:

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Which will have a greater volume: 10 grams of liquid water or 10 grams of solid water?

san4es73 [151]

The volume of 10 grams of frozen water is more than the volume of 10 grams of liquid water

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3 years ago

A sample of N2 gas in a flask is heated from 27 Celcius to 150 Celcius. If the original gas is @ pressure of 1520 torr, what is

Romashka [77]

Answer:

$\large \boxed{\text{B.) 2.8 atm}}$

Explanation:

The volume and amount are constant, so we can use Gay-Lussac’s Law:

At constant volume, the pressure exerted by a gas is directly proportional to its temperature.

$\dfrac{p_{1}}{T_{1}} = \dfrac{p_{2}}{T_{2}}$

Data:

p₁ = 1520 Torr; T₁ = 27 °C

p₂ = ?; T₂ = 150 °C

Calculations:

(a) Convert the temperatures to kelvins

T₁ = ( 27 + 273.15) K = 300.15 K

T₂ = (150 + 273.15) K = 423.15 K

(b) Calculate the new pressure

$\begin{array}{rcl}\dfrac{1520}{300.15} & = & \dfrac{p_{2}}{423.15}\\\\5.064 & = & \dfrac{p_{2}}{423.15}\\\\5.064\times423.15&=&p_{2}\\p_{2} & = & \text{2143 Torr}\end{array}\\$

(c) Convert the pressure to atmospheres

$p = \text{2143 Torr} \times \dfrac{\text{1 atm}}{\text{760 Torr}} = \textbf{2.8 atm}\\\\\text{The new pressure reading will be $\large \boxed{\textbf{2.8 atm}}$}$

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2 years ago

Calculate the number of moles of a gas that is present in a 7.55 L container at 45°C, if the gas exerts a pressure of 725mm Hg.

vovikov84 [41]

Answer: The number of moles of gas present is 0.276 moles

Explanation:

To calculate the number of moles of gas, we use the equation given by ideal gas:

PV = nRT

where,

P = Pressure of the gas = 725 mm Hg

V = Volume of the gas = 7.55 L

n = number of moles of gas = ?

R = Gas constant = $62.3637\text{ L.mmHg }mol^{-1}K^{-1}$

T = Temperature of the gas = $45^oC=(45+273)K=318K$

Putting values in above equation, we get:

$725mmHg\times 7.55L=n\times 62.3637\text{ L.mmHg }mol^{-1}K^{-1}\times 318K\\\\n=0.276mol$

Hence, the number of moles of gas present is 0.276 moles

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3 years ago

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olga2289 [7]

Answer:

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Explanation:

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It is noticed as a brown haze above cities. The negative effects are: production of chlorofluorocarbons (CFCs) increased UV radiation, irritation to the eyes, nose, and throat.

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3 years ago