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3 years ago

At this pressure, how many molecules of air would there be in a 20 ∘C experimental chamber with a volume of 0.020 m3 ?

Chemistry

1 answer:

jonny [76]3 years ago

8 0

Answer:

Explanation: The lowest pressure in a laboratory is 4.0×10^-11Pa

Using Ideal gas equation

PV = nRT

P= 4.0×10^-11Pa

V= 0.020m^3

T= 20+273= 293k

n=number of moles = m/A

Where m is the number of molecules and A is the Avogradro's number=6.02×10²³/mol

R=8.314J/(mol × K)

PV= m/A(RT)

4.0×10^-11 ×0.020 = m/6.02×10²³(8.314×293)

m = 4.0×10^-11×0.020×6.02×10^23 / (8.314×293)

m = 1.98×10^8 molecules

Therefore,the number of molecules is 1.98×10^8

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If a falling rock undergoes a Δv of 112ms due to an a¯¯¯ of 9.8 m/s2, how long did it fall? A. 6.7 seconds B. 11.4 seconds C. 0.

tresset_1 [31]

Answer:

9.8

Explanation:

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3 years ago

Select all that apply. Atoms are made up of _____. protons neutrons compounds elements electrons

charle [14.2K]

Answer:

protons, nuetrons, electrons

Explanation:

compounds and electrons are made up of atoms.

8 0

3 years ago

Calculate the following:

Brrunno [24]

Follow these steps to solve the given equation:

Multiply the two decimal figures together and find the sum of the exponents, that is,

(1.5 * 1.89) * 10 ^4+3

(2.835) * 10^7

10^7 can also be written as e.70

'e' stands for exponential.

Therefore, we have 2. 835 e 7.0 = 2.8 e 7.0.

Based on the calculations above, the correct option is A.

4 0

3 years ago

To separate a mixture of iron filings and salt, the most efficient method would be

GaryK [48]

Answer:

Explanation:

Of course you could do the separation chemically. Dissolve the salt up in water, pass thru a filter, wash the iron filings with ethanol, which would encourage the salt to precipitate from solution.

I do hope I helped you! :)

4 0

3 years ago

What is the oh- in a solution with a poh of 5.71

Rudik [331]

Answer:- The hydroxide ion concentration of the solution is $1.95*10^-^6$ .

Solution:- The formula used to calculate pOH from hydroxide ion is:

$pOH=-log[OH^-]$

When pOH is given and we are asked to calculate hydroxide ion concentration then we multiply both sides by negative sign and take antilog and what we get on doing this is:

$[OH^-]=10^-^p^O^H$

pOH is given as 5.71 and we are asked to calculate hydrogen ion concentration. Let's plug in the given value in the formula:

$[OH^-]=10^-^5^.^7^1$

$[OH^-]$ = 0.00000195 or $1.95*10^-^6$

So, the hydroxide ion concentration of the solution is $1.95*10^-^6$ .

3 0

3 years ago