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Luden [163]
3 years ago
12

Which of the following is NOT an example of a chemical change?

Chemistry
2 answers:
puteri [66]3 years ago
5 0
I think it’s C...........
Katyanochek1 [597]3 years ago
4 0

Answer:

hi there !!

B) Water evaporates into steam.

this is correct because only physical state changes, steam can be cooled down to get water again.

You might be interested in
How many protons are there in one atom of hydrogen
borishaifa [10]

Answer:

There is only one proton because it has a molecular mass of one

3 0
3 years ago
What is the number of moles of solute in a .3 molality solution containing .10 kg of solvent?
denpristay [2]
Concentration can be expressed in different forms: molarity, molality, normality, percentage, part per million and many more. For molality, it is a unit of concentration expressed as moles of solute per kilogram of solvent. Therefore,

0.3 = moles solute/0.10 kg solvent
moles solute = 0.03 moles
4 0
3 years ago
Read 2 more answers
Why would you need to heat the hydrate up to 250 degrees if water boils at 100 degrees Celsius? Do you think that the boiling po
sergeinik [125]

Explanation:

The pure form of water has a boiling point of 100°C. Boiling point is a physical property of matter and it shows that at such temperature, a liquid substance will change state to vapor.

Pure water is made up of 2 atoms of hydrogen and 1 atom of oxygen. The only intermolecular forces between them is the hydrogen bonds that must be broken for the water to boiling off.

In hydrate, water is present in another form. The water is attached to another compound.

For a pure liquid, the they have reasonably constant boiling point and low boiling range.

Impurities such as the other part of the hydrate causes the elevation of the boiling point and the widening of the boiling range for impure substances.

We are no longer dealing with just hydrogen bonds, other molecular interactions are now involved and they need to be accounted for.

learn more:

Pure substances brainly.com/question/1832352

#learnwithBrainly

8 0
4 years ago
A 0.271g sample of an unknown vapor occupies 294ml at 140C and 874mmHg. The emperical formula of the compound is CH2. How many m
Phoenix [80]
Using PV = nRT, we can calculate the moles of the sample.
874 mmHg = 116,524 Pa
n = PV/RT
n = 116,524 x 294 x 10⁻⁶ / 8.314 x (140 + 273)
n = 9.98 x 10⁻³ mol

moles = mass / Mr
Mr = 0.271/9.98 x 10⁻³
Mr = 27.2
Mass of empirical formula = 14
Repeat units = 27.2 / 14 ≈ 2

Formula of substance:
C₂H₄

Combustion equation:
C₂H₄ + 3O₂ → 2CO₂ + 2H₂O

1 mole produces 2 moles of CO₂, so 3 moles will produce 6 moles CO₂
7 0
3 years ago
How many moles are equal to 89.23g of calcium oxide, CaO?
Katen [24]

1.59moles

Explanation:

Mass  of CaO = 89.23g

Unknown

Number of moles = ?

Solution:

The mole is a unit of measurement in chemistry used to delineate the number of particles an atom contains.

A mole of a substance contains the avogadro's number of particles.

Number of moles = \frac{mass}{molar mass}

Molar mass of CaO = 40 + 16 = 56g/mol

  Number of moles = \frac{89.23}{56} = 1.59moles

learn more:

Number of moles brainly.com/question/1841136

#learnwithBrainly

8 0
3 years ago
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