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love history [14]
3 years ago
10

Which of the changes are physical changes

Chemistry
1 answer:
Orlov [11]3 years ago
3 0

Answer:

boiling, melting, freezing, and shredding.

Explanation:

Some examples.

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The solubility of KNO3(s) in water increases as the..
makvit [3.9K]
The answer would be b. Temperature of the solution increases 

Temperature determines the kinetic energy of the water molecule. Higher temperature will cause the molecule to moves faster and the compound (KNO3) could break solute molecule easier make it become more soluble. A higher pressure will increase the solubility of a gas, not solid


4 0
3 years ago
The most useful ore of aluminum is bauxite, in which Al is present as hydrated oxides, Al2O3 * xH2O.
lesantik [10]

Answer:

44.7 kWh

Explanation:

Let's consider the reduction of Al₂O₃ to Al in the Bayer process.

6 e⁻ + 3 H₂O + Al₂O₃ → 2 Al + 6 OH⁻

We can establish the following relations:

  • The molar mass of Al is 26.98 g/mol.
  • 2 moles of Al are produced when 6 moles of e⁻ circulate.
  • 1 mol of e⁻ has a charge of 96468 c (Faraday's constant).
  • 1 V = 1 J/c
  • 1 kWh = 3.6 × 10⁶ J

When the applied electromotive force is 5.00 V, the energy required to produce 3.00 kg (3.00 × 10³ g) of aluminum is:

3.00 \times 10^{3} gAl.\frac{1molAl}{26.98gAl} .\frac{6mole^{-}}{2molAl}.\frac{96468c}{1mole^{-}}.\frac{5.00J}{c}.\frac{1kWh}{3.6 \times 10^{6}J} =44.7kWh

6 0
3 years ago
How would you determine which isotope pair to use for a particular material?
VLD [36.1K]

Answer:

Different types of isotopes are used for different materials or objects. For radiometric dating, uranium-235 is considered best for it while carbon-14 is used for dating of rocks. It is also used for dating of wood samples.

Explanation:

Carbon-14 and uranium-235 are used for different materials or objects for measuring the age of these materials. These two isotopes are radioactive in nature which means they emit gamma radiations which allow us to find the age of different objects. Carbon-14 has a low half life so it can be used for those objects which are present before thousands of years while uranium-235 is used for materials which are millions of years old due to high half life.

7 0
3 years ago
What is the molecular formula of a compound if its emprical formula is NO2 and its molar mass is 138.02 g/mole
Ratling [72]

Answer:

N₃O₆  

Step-by-step explanation:

Data:

EF = NO₂

MM = 138.02 g/mol

Calculations:

EF Mass = (14.01 + 32.00) u

EF Mass = 46.01 u

The molecular formula is an integral multiple of the empirical formula.

MF = (EF)ₙ

  n = MF Mass/EF Mass  

  n = 138.02 u/46.01 u  

  n = 3.000 ≈3

MF = (NO₂)₃

MF = N₃O₆

7 0
3 years ago
How many atoms are in 5 moles of sodium hydroxide
Yuki888 [10]

5000000algomas  enos ai spor lo menos orspondi

em

7 0
3 years ago
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