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2 years ago

Why is copper a pure substance? a. because it is an element b. because it is a compund c. because it is a homogenous mixture

Chemistry

1 answer:

Step2247 [10]2 years ago

6 0

Answer:

a. because it is an element

Explanation:

its pure because it only has one type of atom, making it an element

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over a 12.3 minuete period 5.13 E-3 moles of F2 gas effuses from a contaier. How many moles of CH4 gas could effuse from from th

Aleonysh [2.5K]

Answer : The moles of methane gas could be, $7.90\times 10^{-3}mol$

Solution :

According to the Graham's law, the rate of effusion of gas is inversely proportional to the square root of the molar mass of gas.

$R\propto \sqrt{\frac{1}{M}}$

or,

$(\frac{R_1}{R_2})=\sqrt{\frac{M_2}{M_1}}$

$[\frac{(\frac{n_1}{t_1})}{(\frac{n_2}{t_2})}]=\sqrt{\frac{M_2}{M_1}}$

where,

$R_1$ = rate of effusion of fluorine gas

$R_2$ = rate of effusion of methane gas

$n_1$ = moles of fluorine gas = $5.13\times 10^{-3}mol$

$n_2$ = moles of methane gas = ?

$t_1=t_2$ = time = 12.3 min (as per question)

$M_1$ = molar mass of fluorine gas = 38 g/mole

$M_2$ = molar mass of methane gas = 16 g/mole

Now put all the given values in the above formula 1, we get:

$[\frac{(\frac{5.13\times 10^{-3}mol}{12.3min})}{(\frac{n_2}{12.3min})}]=\sqrt{\frac{16g/mole}{38g/mole}}$

$n_2=7.90\times 10^{-3}mol$

Therefore, the moles of methane gas could be, $7.90\times 10^{-3}mol$

8 0

3 years ago

Calculate the volume occupied by 55.5 moles of water at STP.

Tems11 [23]

Answer:

Volume occupied by 55.5 moles of water gas at STP = 1240 Liters.

Explanation:

1st keep in mind that 'volume' in the context of problems like this apply only to the gas phase form of the substance. Water in solid form (ice) or liquid form (liquid water) do not apply. Volume in this case is referred to as 'molar volume' and is a gas occupying 22.4 liters at STP conditions (0°C, 1Atm).

So, if 1 molar volume of water gas (steam) occupies 22.4 Liters at STP, then 55.5 moles of water gas occupies 22.4 Liters/mole x 55.5 moles = 1243.2 Liters, or 1240 Liters (3 sig. figs.). :-)

4 0

3 years ago

HELP ITS DUE IN 5 MINS PLSSS Name at least one negative affect that is the result of clearing areas of a rainforest.

Dimas [21]

Global warming

Carbon dioxide is released into the air, causing global warming.

6 0

3 years ago

Read 2 more answers

** worth 20 points + brainliest **

Bad White [126]

Answer : The correct option is, (D) $83^oC$

Solution :

Formula used :

$Q=m\times c\times \Delta T=m\times c\times (T_{final}-T_{initial})$

where,

Q = heat released = -1300 J

m = mass of water = 40 g

c = specific heat of water = $4.18J/g^oC$

$\Delta T=\text{Change in temperature}$

$T_{final}$ = final temperature = ?

$T_{initial}$ = initial temperature = $91.0^oC$

Now put all the given values in the above formula, we get the final temperature of water.

$-1300J=40g\times 4.18J/g^oC\times (T_{final}-91.0^oC)$

$T_{final}=83.2^oC\approx 83^oC$

Therefore, the final temperature of the water is, $83^oC$

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3 years ago

Briefly explain formality in solution.

Zielflug [23.3K]

Answer:

Both molarity and formality express concentration as moles of solute per liter of solution. Formality is a substance's total concentration in solution without regard to its specific chemical form. ... The formality of a solution is defined as the number of formula mass of any solute dissolved in 1 litre of solution.

4 0

3 years ago