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Sever21 [200]
2 years ago
15

Which ones are physical change and which ones are chemical reactions:

Chemistry
1 answer:
Sonbull [250]2 years ago
8 0
Physical change- evaporation , condensation
Chemical change- combustion , neutralization
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Dr. I. M. A. Brightguy adds 0.1727 g of an unknown gas to a 125-mL flask. If Dr. B finds the pressure to be 736 torr at 20.0°C,
AlladinOne [14]

Answer:

The gas that Dr. Brightguy added was O₂

Explanation:

Ideal Gases Law to solve this:

P . V = n . R . T

Firstly, let's convert 736 Torr in atm

736 Torr is atmospheric pressure = 1 atm

20°C = 273 + 20 = 293 T°K

125 mL = 0.125L

0.125 L . 1 atm = n . 0.082 L.atm / mol.K . 293K

(0.125L .1atm) / (0.082 mol.K /L.atm . 293K) = n

5.20x10⁻³ mol = n

mass / mol = molar mass

0.1727 g / 5.20x10⁻³ mol = 33.2 g/m

This molar mass corresponds nearly to O₂

7 0
3 years ago
A 5.00g of X, the product of organic synthesis is obtained in a 1.0 dm3 aqueous solution. Calculate the mass of X that can be ex
Anestetic [448]

Answer:

mass of X extracted from the aqueous solution by 50 cm³ of ethoxy ethane = 3.33 g

Explanation:

The partition coefficient of X between ethoxy ethane (ether) and water, K is given by the formula

K = concentration of X in ether/concentration of X in water

Partition coefficient, K(X) between ethoxy ethane and water = 40

Concentration of X in ether = mass(g)/volume(dm³)

Mass of X in ether = m g

Volume of ether = 50/1000 dm³ = 0.05 dm³

Concentration of X in ether = (m/0.05) g/dm³

Concentration of X in water = mass(g)/volume(dm³)

Mass of X in water left after extraction with ether = (5 - m) g

Volume of water = 1 dm³

Concentration of X in water = (5 - m/1) g/dm³

Using K = concentration of X in ether/concentration of X in water;

40 = (m/0.05)/(5 - m)

(m/0.05) = 40 × (5 - m)

(m/0.05) = 200 - 40m

m = 0.05 × (200 - 40m)

m = 10 - 2m

3m = 10

m = 10/3

m = 3.33 g of X

Therefore, mass of X extracted from the aqueous solution by 50 cm³ of ethoxy ethane = 3.33 g

8 0
3 years ago
What is freshly pumped oil called?
algol13

Answer:

When the drill hits oil, some of the oil rises from the ground high into the air. This immediate release of oil is known as a "gusher." Once a reservoir has been located, pumps are used to extract the oil.

7 0
2 years ago
Read 2 more answers
Consider the heating curve of H2O and line segments A, B, and C. Several changes are taking place at A, B, and C. All BUT ONE wo
Tamiku [17]

Explanation:

The answer is space between molecules decreases.

Hope this helps .>.

3 0
3 years ago
Read 2 more answers
A. 0.5 m/s<br>b. 0.75 m/s<br>c. 2 m/s<br>d. 3 m/s ​
GenaCL600 [577]

Answer:

Option a. 0.5 m/s

Explanation:

This graph shows a straight line, where "Y" axis would be "Position" and "X" graph would be "Time". The ecuation that would describe this straight line is Y= aX + 1 , where "a" is the slope or inclination for this graph, and would give us the speed of the object

How do we find the slope (and hence, the speed)?: if you notice this graph, you will check that:

-When X (Time) is zero, Y (Position) is 1

-When X (Time) is 2, Y (Position) is 2

With these 4 points, you can calculate the slope (which will call "m") for this graph with:

m = (Y2-Y1)/(X2-X1)   so: Y2=2, Y1=1, X2=2, X1=0

Which gives us: m=1/2 (0.5), the slope or speed of the object: 0.5 m/s

4 0
3 years ago
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