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2 years ago

Can a physical change, change what a substance is? Exp

1 answer:

7 0

Physical changes are changes affecting the form of a chemical substance, but not its chemical composition. Physical changes are used to separate mixtures into their component compounds, but can not usually be used to separate compounds into chemical elements or simpler compounds.

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Each polysaccharide tested gives different color results with the iodine test

fomenos

Iodine (iodine-potassium iodide) staining distinguishes starch ( a polysaccharide) from monosaccharides, a disaccharides and other polysaccharides. Therefore, a bluish black color is a positive test for starch, and a yellow-ish brown color ( no color change) is a negative test for starch.

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2 years ago

Por ser la materia electrica neutra ¿como debe de ser el numero de electrones y el de protones?

kvasek [131]

Answer:

Deben ser de igual número.

Explanation:

8 0

1 year ago

Identify the oxidized substance, the reduced substance, the oxidizing agent, and the reducing agent in the redox reaction. Cu(s)

spin [16.1K]

Answer: Copper is getting oxidized and is a reducing agent. Silver is getting reduced and is oxidizing agent.

Explanation:

Oxidation reaction is defined as the reaction in which an atom looses its electrons. Here, oxidation state of the atom increases.

$X\rightarrow X^{n+}+ne^-$

Reduction reaction is defined as the reaction in which an atom gains electrons. Here, the oxidation state of the atom decreases.

$X^{n+}+ne^-\rightarrow X$

Oxidizing agents are defined as the agents which oxidize other substance and itself gets reduced. These agents undergoes reduction reactions.

Reducing agents are defined as the agents which reduces the other substance and itself gets oxidized. These agents undergoes reduction reactions.

For the given chemical reaction:

$Cu(s)+2AgNO_3(aq.)\rightarrow 2Ag(s)+Cu(NO_3)_2(aq.)$

The half reactions for the above reaction are:

Oxidation half reaction: $Cu(s)\rightarrow Cu^{2+}(aq.)+2e^-$

Reduction half reaction: $2Ag^+(aq.)+2e^-\rightarrow 2Ag(s)$

From the above reactions, copper is loosing its electrons. Thus, it is getting oxidized and is considered as a reducing agent.

Silver is gaining electrons and thus is getting reduced and is considered as an oxidizing agent.

4 0

3 years ago

3. Dorji was provided with four colourless solutions. He was asked to

givi [52]

Answer:

First, we can test Solution 1. We know that Sodium Hydroxide is a strong base. If we test acids on blue litmus paper, they will turn red. If we test bases on red litmus paper, they will turn blue. So, you can test all the of the solutions- water, sodium hydroxide and hydrochloric acid with blue and red litmus paper. HCl, Hydrochloric acid is an acid, so it will turn blue litmus paper red. It will not turn red litmus blue. The acids will turn blue litmus paper red. The bases will turn red litmus paper blue. Only water is a neutral liquid, which will not turn blue litmus paper red or red litmus paper blue. It will not change the colour of it. Thus, if you test all the solutions with blue and red litmus paper, you will know which solution is water. Water is the only one which is neutral. It is the only solution which cannot change the colour of any litmus paper. Thus, you can identify it very easily.

5 0

2 years ago

An atom has the following electron configuration 1s2s2sp63s23p64s2 How many valance electrons does this atom have?

JulijaS [17]

Answer:

The electron configuration for this atom is Calcium, which has 2 valence electrons.

Explanation:

Following the periodic table and with the electron configuration, you will end up with calcium, which has 2 valence electrons. (Always follow the electron configuration from left to right! It begins at hydrogen, then to helium... and so on.)

1s2 -> He....

2s2 -> Be....

2p6 -> Ne...

3s2 -> Mg...

3p6 -> Ar...

4s2 -> Ca.

6 0

2 years ago