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Maslowich
3 years ago
8

Which of the following is an example of a chemical change?

Chemistry
2 answers:
Lynna [10]3 years ago
6 0
The answer is burning paper

svetoff [14.1K]3 years ago
4 0
Burning paper...chemical changes are permanent and can't return to original form.<span />
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A rigid tank contains 0.66 mol of oxygen (O2). Find the mass of oxygen that must be withdrawn from the tank to lower the pressur
dsp73

Answer:

12.8 g of O_{2} must be withdrawn from tank

Explanation:

Let's assume O_{2} gas inside tank behaves ideally.

According to ideal gas equation- PV=nRT

where P is pressure of O_{2}, V is volume of O_{2}, n is number of moles of O_{2}, R is gas constant and T is temperature in kelvin scale.

We can also write, \frac{V}{RT}=\frac{n}{P}

Here V, T and R are constants.

So, \frac{n}{P} ratio will also be constant before and after removal of O_{2} from tank

Hence, \frac{n_{before}}{P_{before}}=\frac{n_{after}}{P_{after}}

Here, \frac{n_{before}}{P_{before}}=\frac{0.66mol}{43atm} and P_{after}=17atm

So, n_{after}=\frac{n_{before}}{P_{before}}\times P_{after}=\frac{0.66mol}{43atm}\times 17atm=0.26mol

So, moles of O_{2} must be withdrawn = (0.66 - 0.26) mol = 0.40 mol

Molar mass of O_{2} = 32 g/mol

So, mass of O_{2} must be withdrawn = (32\times 0.40)g=12.8g

7 0
2 years ago
What is the most specific classification of Ca(NO3)2
Cerrena [4.2K]
"Compound" is the one among the following choices given in the question that is the <span>most specific classification of Ca(NO3)2. The correct option among all the options that are given in the question is the second option. It is actually an inorganic compound. I hope that this is the answer that has come to your help.</span>
7 0
2 years ago
Read 2 more answers
We discussed the different types of intermolecular forces in this lesson. Which type would you expect to find in CO2?
g100num [7]

Answer:

Dispersion forces.

Explanation:

CO2 contains dispersion forces, and covalent bonds. It is a linear molecule, and the bond angle of O-C-O is 180 degree. O is more electronegative than C, the C-O contains polar bond with the having negative end pointing towards the O.

CO contains two C-O bonds. They cancel each other out because of the dipoles point in opposite directions. Although, CO2 contains polar bonds, it is known as a nonpolar molecule. So, the only intramolecular forces which CO2 having are London dispersion forces.

5 0
3 years ago
Which statements correctly describe atmospheric pressure?
Shalnov [3]

Answers are:

2. It pushes on all objects that are on Earth’s surface.

3. It can be measured in atmospheres or kilopascals.

Barometric pressure (atmospheric pressure), is the pressure within the atmosphere of Earth

Atmospheric pressure decreases with increasing height, because there are fewer air molecules above a given object.

Barometer is an instrument used in meteorology to measure atmospheric pressure.

Atmospheric pressure (atm) is the force per unit area by the weight of air above that point.  

Kilopascal (kPa) is a metric system pressure unit and equals to 1000 force of newton per square meter.

Atmospheric pressure results from molecular collisions of atmospheric gases.

4 0
2 years ago
Consider the reaction:
goldfiish [28.3K]

Answer:

K = Ka/Kb

Explanation:

P(s) + (3/2) Cl₂(g) <-------> PCl₃(g) K = ?

P(s) + (5/2) Cl₂(g) <--------> PCl₅(g) Ka

PCl₃(g) + Cl₂(g) <---------> PCl₅(g) Kb

K = [PCl₃]/ ([P] [Cl₂]⁽³'²⁾)

Ka = [PCl₅]/ ([P] [Cl₂]⁽⁵'²⁾)

Kb = [PCl₅]/ ([PCl₃] [Cl₂])

Since [PCl₅] = [PCl₅]

From the Ka equation,

[PCl₅] = Ka ([P] [Cl₂]⁽⁵'²⁾)

From the Kb equation

[PCl₅] = Kb ([PCl₃] [Cl₂])

Equating them

Ka ([P] [Cl₂]⁽⁵'²⁾) = Kb ([PCl₃] [Cl₂])

(Ka/Kb) = ([PCl₃] [Cl₂]) / ([P] [Cl₂]⁽⁵'²⁾)

(Ka/Kb) = [PCl₃] / ([P] [Cl₂]⁽³'²⁾)

Comparing this with the equation for the overall equilibrium constant

K = Ka/Kb

5 0
3 years ago
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