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Andrej [43]
3 years ago
13

Which of these can be classified as a pure substance? Help please

Chemistry
2 answers:
saw5 [17]3 years ago
4 0

Answer: The answer is salt

nikdorinn [45]3 years ago
4 0
The pure substance is salt.
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4. What is the total mass of ice that can be vaporized by 2100 kJ of heat energy?
anygoal [31]

Answer:

5 g

Explanation:

The heat required to vaporize ice is the sum of

i) Heat required to melt ice at 0°C

ii) Heat required to raise the temperature from  0°C to 100°C

iii) Heat required to vaporize water at 100°C

Thus;

H = nLfus + ncθ + nLvap

H= n(Lfus + cθ + Lvap)

Lfus = 6.01 kJ/mol

Lvap = 41 kJ/mol

c = 75.38

n =?

2100 = n(6.01  + 75.38(100) + 41)

n = 2100 KJ/7585.01 kJ/mol

n = 0.277 moles

Mass of water = number of moles * molar mass

Mass of water = 0.277 moles * 18 g/mol

Mass of water =  5 g

3 0
3 years ago
A 3.0 g sample of a gas occupies a volume of 1.00L at 100C and 740 torr pressure. The molecular weight of the
SOVA2 [1]

Answer:

94.2 g/mol

Explanation:

Ideal Gases Law can useful to solve this

P . V = n . R . T

We need to make some conversions

740 Torr . 1 atm/ 760 Torr = 0.974 atm

100°C + 273 = 373K

Let's replace the values

0.974 atm . 1 L = n . 0.082 L.atm/ mol.K . 373K

n will determine the number of moles

(0.974 atm . 1 L) / (0.082 L.atm/ mol.K . 373K)

n = 0.032 moles

This amount is the weigh for 3 g of gas. How many grams does 1 mol weighs?

Molecular weight → g/mol → 3 g/0.032 moles = 94.2 g/mol

3 0
3 years ago
how is substitution reaction in alkanes different from dehydrogenation reaction since both involve removing a hydrogen atom from
Ilia_Sergeevich [38]

Answer:

See Explanation

Explanation:

A substitution reaction means the replacement of one or more hydrogen atoms in an alkane by another atom or group. It does not introduce a double bond into the product. The product retains single bonds between the species present.

For instance;

CH4 + Cl2 -------> CH3Cl +HCl

is a substitution reaction

Dehydrogenation is the process of removing two hydrogen atoms from a saturated compound compound thereby yielding an unsaturated product.

E.g

C2H6 --------->C2H4 + H2

The key difference is that substitution reaction yields a saturated product while dehydrogenation yields an unsaturated product.

8 0
3 years ago
Why are plant cells and animal cells different
Alenkinab [10]
The Plant cell has cell walls to prevent it from basting in case of large amount of water.
while the animal cell doesn't have cell walls.
                 
                                  P.S. PHANTOM SNIPERS
5 0
3 years ago
The chemical formula for oxygen difluoride is O2F true or false?
Dahasolnce [82]

Answer:

false

Explanation:

5 0
3 years ago
Read 2 more answers
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