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3 years ago

Explain the changes that take place at the molecular level when a substance is superheated or supercooled ?

1 answer:

4 0

Only gas or vapor can be superheated. Use water as an example. Water at sea level boils at 212 degrees F. When heated to 212 degrees F, the molecules that make up water are moving at a high enough speed that they overcome the air pressure above the water. And for supercooled only liquids or solids can be supercooled for example Liquid water at sea level has a saturation (boiling) temperature of 212 degrees F. If we were to add heat to the saturated water, it would first boil away with no change in temperature (remember latent heat?) and then become superheated if still more heat were added to the vapor (steam) after it had all turned to a vapor.

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The molar mass of the compound was found to be 30.069 g/mol. what is the molecular formula? express your answer as a chemical fo

kodGreya [7K]

For us to accurately determine what compound this is, additional info must be given. However I can suggest two compounds which have molecular mass of about 30.07 g/mol.

1. It could be NO or nitric oxide.

The molecular mass is 16 + 14= 30 g/mol

But if we search the exact weight, it is 30.01 g/mol

2. It could also be (CH3)2 or ethane.

The molecular mass is 2*12+ 6*1= 30 g/mol

But if we search the exact weight, it is 30.07 g/mol.

<span>So we could say it more likely to to be (CH3)2 </span>

6 0

3 years ago

When both –NH2 and –COOH replace hydrogen atoms on the same carbon atom, a(n) ____ is formed. a. amine c. carboxylic acid b. ami

Mice21 [21]

$-NH_{2}$ represents amine functional group and $COOH$ represents carboxylic acid functional group. When these both functional groups are substituted onto a single carbon atom, then amino acid is formed.

The organic compound consists of $-NH_{2}$ functional group and $COOH$ functional group with a side chain is said to be an amino acid.

A: amine group is $-NH_{2}$ .

C: carboxylic acid group is $COOH$

B: amino acid represents $-NH_{2}$ functional group and $COOH$ functional group which are substituted onto a single carbon atom.

D: carbohydrate: the general formula of carbohydrate is $(CH_{2} O)_{x}$ .

Hence, amino acid is the correct answer.

4 0

3 years ago

QUESTION 3

Blababa [14]

These questions are all about indirect and direct variation with PV=nRT, the ideal gas equation

Q3.
false, because of PV=nRT, the ideal gas equation if V goes up, P has to go down to equal nRT

Q4. false, if V remains constant, and P and T are constant as moles of gas are added, then something is wrong becse something has to change when stuff is added (V has to go down)

Q5.
PV=nRT
when T and n are constant, (R is the gas constant)
PV=k, aka V=k/P which means inversly proportional

TRUE

Q6.
ggeasy
refer to past question
PV=k
if P is doubled then V has to halve in order to equal k
1/2 times 2=1
volume is halved

Q7. use charles law
V/T=k
so
given
V=4
T= kelvins, so 299
4/299=k
so when temp goes to 22 does V go to 3.95
4/299=3.95/295?
true
because they're equal

Q8
FALSE, must be used in kelvins
T=absolute tempurature in kelvins

Q9
PV=nRT
solve for T
(PV)/(nR)=T

use final volumes and pressures
P=5atm
V=24L
n=1
R=0.082057 atm L/(mol K)
(5atm*24L)/(1mol*0.082057 atm L/mol K)=T
see, if you didn't mess up, the units cancel nicely
T=1462.4
1200 K is closest

Q10
PV/T=constant because moles are constant (supposedly)

V=4L
P=2.08atm
T=275K

so find initial to final is constant
(2.08atm*4L)/(275K)=(Pfinal*2.5L)/(323K)
solve for Pfinal
Pfinal=3.92315 atm
answer is 3.9atm

Merry Christmas

4 0

4 years ago

You have been given an orange liquid and told to describe its properties.

chubhunter [2.5K]

Answer:

The correct answer would be - observing with the help of five senses.

Explanation:

To find and describe the physical properties of the given substance or the solution or liquid students can observe using their five senses. By looking at the liquid one can find its state and color, by smelling students can find the odor of the sample, by touching it one can observe and describe the texture.

Fluidity can also be measure by the touch if the solution is viscous or free-floating. By using a thermometer and using a graduated cylinder one can find the temperature at room temperature and the weight of substance respectively.

5 0

4 years ago

Chemical reaction occurs when the chemical identity of the reactants is different from that of the products. A new substance for

nikdorinn [45]

Answer:

Explanation:

Exothermic: the surrounds feel warmer. A wood fire stove is a good example of an exothermic reaction. You can feel the heat on your hands. It's exothermic.

Endothermic is exactly the opposite. The reaction takes place, but the heat comes from the surroundings. When you touch something that goes through an endothermic reaction, it feels much cooler.

This reaction, just by definition is endothermic.

5 0

3 years ago