1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
sweet [91]
2 years ago
5

Compare the type of change that occurs when an iron bar rusts and when a substance freezes.

Chemistry
1 answer:
Ivanshal [37]2 years ago
5 0

Explanation:

when an iron bar rust is an example of a chemical change in which a new substance is formed and the change is not easily reversible.for iron to rust moisture and air must be present.while when a substance freezes,it can be easily reversed through melting and no new substance is formed.this change is termed a physical change.

You might be interested in
A medical research lab in Europe is studying a drug’s absorption in the blood. Another lab in Japan is trying to delay the elimi
ladessa [460]

The correct answer is From different social and ethnic backgrounds.

Explanation:

The purpose of science studies is to gain an understanding of specific phenomena and use this in the benefit of the world or humanity. Moreover, science is guided by objective methods and these are applied all around the world. This feature allows scientists from all kinds of social and ethnic backgrounds to study the same phenomena and obtain similar results, which is essential for the progress of scientific knowledge. This is exemplified by two different labs in two different countries studying drug absorption because the results of these two studies can be analyzed together to understand drug absorption.

In this context, one factor that contributes to the progress of scientific knowledge is the effort of scientists "from different social and ethnic backgrounds".

7 0
3 years ago
Calculate the dissociation constant of nh4oh(aq) if the degree of dissociation of 0.006 mol/kg solution is 0.053 and the activit
Anastasy [175]

The dissociation equation will be

                         NH4OH   --->        NH4+                   + OH-

Initial                 0.006                        0                          0

Change         -0.006 X 0.053        +0.006 X 0.053      -0.006 X 0.053

Equlibrium     0.006 -0.006 X 0.053      0.006 X 0.053    0.006 X 0.053

Ka = [NH4+] [ OH-] / [NH4OH] = (0.006 X 0.053)^2 / 0.006 -0.006 X 0.053

Ka = 1.78 X 10^-5

7 0
3 years ago
Separate this redox reaction into its component half-reactions. 3o2 4co
swat32
The equation is:
3 O₂ + 4 Co → 2 Co₂O₃
Oxidation half reaction:
Co → Co³⁺ + 3 e
Reduction half reaction:
O₂ + 4 e → 2 O²⁻
To balance the equation number of electrons lost must be equal to number or electrons gained so we must multiply oxidation half time 4 and reduction half times 3
3 0
3 years ago
How much potassium chloride is needed to make 0.500 m solution with 1.50 L of water?
Andrew [12]

Answer:

55.9 g KCl.

Explanation:

Hello there!

In this case, according to the definition of molality for the 0.500-molar solution, we need to divide the moles of solute (potassium chloride) over the kilograms of solvent as shown below:

m=\frac{mol}{kilograms}

Thus, solving for the moles of solute, we obtain:

mol=m*kilograms

Since the density of water is 1 kg/L, we obtain the following moles:

mol=0.500mol/kg*1.50kg\\\\mol=0.75mol

Next, since the molar mass of KCl is 74.5513 g/mol, the mass would be:

0.75mol*\frac{74.5513g}{1mol}\\\\55.9g \ KCl

Regards!

4 0
3 years ago
An atom that has an atomic number of 38 and a mass number of 88 is an isotope of an atom that has An atom that has an atomic num
gayaneshka [121]

Answer: Option b. 50 neutrons and 38 protons.

Explanation:

Atomic number = proton number = 38

Mass number = proton number + Neutron

Mass number = 88

Proton = 38

Neutron number =?

Neutron number = Mass number — proton number

Neutron number = 88 —38 = 50

3 0
3 years ago
Other questions:
  • What is the main cause of any change of state?
    6·2 answers
  • Which of the following is one way that land contributes to production?
    12·2 answers
  • What is the most common type of climate/ecosystem found in the Congo River basin?
    10·2 answers
  • How many grams of a 31.6% potassium sulfate solution would contain 617 g potassium sulfate?
    13·1 answer
  • If you have 100.0ml of a 30.0% aqueous solution of ethanol, what volume of water is in the solution?
    5·1 answer
  • Which change would cause an immediate increase in the rate of the forward reaction
    9·1 answer
  • Write and balance the combination reaction for the heating of solid magnesium in the presence of nitrogen gas. In a particular e
    6·1 answer
  • Ionization of sodium dichromate​
    9·1 answer
  • 3. How is the equilibrium position of this reaction affected
    15·1 answer
  • ASAP I WILL GIVE BRAINLIEST!Which arrow represents the change of state described above? The diagram shows changes of state betwe
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!