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allsm [11]
3 years ago
11

C.) Is heating of cobalt (ii) chloride crystals a chemical change or a physical change (Imk)​

Chemistry
1 answer:
miv72 [106K]3 years ago
8 0

Answer: Heating the hydrated forms of cobalt chloride reverses the reactions above, returning cobalt chloride to the blue, water-free, or anhydrous, state. Water is "liberated" in these reactions, known as dehydration reactions.

Explanation:

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"An increase in the price of gasoline will increase the demand for hybrid vehicles." This statement is an example of a positive
-Dominant- [34]

Answer:

True

Explanation:

This is because the statement above fits the definition of a positive economic statement. A Positive economic statement refers to objective statements that can be verified, tested , amended or discarded by consulting available evidence .The statement above can be tested objectively to establish its veracity.

3 0
3 years ago
How many bonds would be needed when bonding 2 atoms of nitrogen to achieve a full octet for both atoms?
andriy [413]

Answer:

3 bonds are needed.

Explanation:

The electrons that are involved in chemical bonding are those in the outer shell of the highest energy level of the atom. The electron configuration of nitrogen (N) is 1s²2s²2p³. That means thy at each nitrogen atom has 5 valence electrons: 2 electrons in the 2s orbital and 3 electrons in the 2p orbital. To fullfil the octet, each nitrogen atom needs 3 electrons. So, they can share each other 3 electrons to form 3 simple bonds. Therefore, the nitrogen molecule (N₂) has 3 bonds involving 6 bonding electrons or a triple bond.

8 0
3 years ago
Define the following terms:
Marrrta [24]

Answer:

a)An endothermic reaction is any chemical reaction that absorbs heat from its environment. The absorbed energy provides the activation energy for the reaction to occur eg Melting of ice, Evaporating liquid water

   b)An Exothermic reaction is a chemical reaction that involves the release of energy in the form of heat or light.eg a spark, flame, or flash), electricity , a battery), or sound , explosion heard when burning hydrogen).

c)By definition an exothermic reaction produces heat as part of it’s process. The heat generated just by being alive is an exothermic process as well. And as such we become aware of when we feel “too cold” or “too hot” and try to either adjust to the conditions we are in, or minimize them, if possible. It is not merely odd, but contrary to intelligent living, that we choose to increase our discomfort and also risk our health by intentionally increasing not only the exothermic reactions we use but also maximize them to our own detriment. In short, the increased use of inefficient exothermic reactions while inexpensive in current evaluations of financial cost are extremely expensive in terms of it’s effect upon living things, including ourselves. It is as though we are choosing our homes to not only be next to a furnace, but as close as possible to the process.

b8

a) it is important to know chemical properties and compounds.] [Chemistry helps our industry produce more materials—such as paints, plastics, iron or steel, cement, kerosene, and also motor oil. Chemistry also helps farmers to enrich the soil with chemicals ... to grow fresh vegetables.]

b)u asked 4 2 l'll give u ten

The 10 Most Important Lab Safety Rules

   The Most Important Lab Safety Rule. ...

   Know the Location of Safety Equipment. ...

   Dress for the Lab. ...

   Don't Eat or Drink in the Laboratory. ...

   Don't Taste or Sniff Chemicals. ...

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8 0
3 years ago
How many mL of a stock 50% (w/v) KNO3 solution are needed to prepare 250 mL of a 20% (w/v) KNO3 solution?
Andre45 [30]

Answer:

100ml of a stock 50% KNO3 solutions are needed to prepare 250ml of a 20% KNO3 solution.

Explanation:

In the given question it is mentioned that

     S1=50%

      V2=250ml

      S2= 20%

We all know that

                     V1S1=V2S2

                     ∴V1=  V2×S2÷S1

                     ∴V1=  V2S2×1/S1

                      ∴V1= 250×20÷50

                       ∴V1= 100ml

 

6 0
3 years ago
Does data from mass spectrometry indicate that modern scientists have made modifications to Dalton''s model? Justify.
Gelneren [198K]
John Dalton was a scientist who proposed that all matter consists of atoms. At this stage, no one had yet discovered neutrons and the nucleus. As a result, Dalton's model consisted of a single atom i.e. the atom was the smallest object. 
A mass spectrometer is an instrument that is able to see what is inside an atom. Scientists have been able to prove that the item is not the smallest object in the world. Atoms are made up of smaller objects called protons, neutrons and electrons. 
We can, therefore, safely conclude that data  from mass spectrometry has helped modern scientists to make modifications to Dalton's model. <span>
</span>
5 0
3 years ago
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