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2 years ago

Please help me with this three questions

Chemistry

1 answer:

zheka24 [161]2 years ago

7 0

Answer:

1. A. Thyroid Gland Function

B. detecting Blood Clots

C. Treating Cancer

2. An example would be how many are used as tracers for diagnostic purposes

3. Beneficial because it gives us ways to eleminate pests, by the sterile insect technique

Number three is kinda iffy a bit difficult to explain it may be explained better in your book.

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The brain, spinal cord, and nerves are all major organs of the ___ system.

lyudmila [28]

Answer:

nervous system

Explanation:

nervous system

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2 years ago

Read 2 more answers

What percent is tungsten made of from soil?

mars1129 [50]

I think i found your answers

4 0

3 years ago

Pls help me. Show proof on why it’s that answer.

natulia [17]

The answer is “the sustainability of the ecosystem” because if the ecosystem isn’t sustainable enough for many different organisms to live in it then the biological diversity of the ecosystem will decrease.

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3 years ago

A chemistry student must write down in her lab notebook the concentration of a solution of sodium hydroxide. The concentration o

taurus [48]

Answer:

The concentration the student should write down in her lab is 2.2 mol/L

Explanation:

Atomic mass of the elements are:

Na: 22.989 u

S: 32.065 u

O: 15.999 u

Molar mass of sodium thiosulfate, Na2S2O3 = (2*22.989 + 2*32.065 + 3*15.999) g/mol = 158.105 g/mol.

Mass of Na2S2O3 taken = (19.440 - 2.2) g = 17.240 g.

For mole(s) of Na2S2O3 = (mass taken)/(molar mass)

= (17.240 g)/(158.105 g/mol) = 0.1090 mole.

Volume of the solution = 50.29 mL = (50.29 mL)*(1 L)/(1000 mL)

= 0.05029 L.

To find the molar concentration of the sodium thiosulfate solution prepared we use the formula:

= (moles of sodium thiosulfate)/(volume of solution in L)

= (0.1090 mole)/(0.05029 L)

= 2.1674 mol/L

6 0

3 years ago

What are the limitations of litmus paper and Phenolphthalein indicators? Name to other indicators that can be used that do not h

jenyasd209 [6]

Answer:

Here's what I find.

Explanation:

An indicator is usually is a weak acid in which the acid and base forms have different colours. Most indicators change colour over a narrow pH range.

(a) Litmus

Litmus is red in acid (< pH 5) and blue in base (> pH 8).

This is a rather wide pH range, so litmus is not much good in titrations.

However, the range is which it changes colour includes pH 7 (neutral), so it is good for distinguishing between acids and bases.

(b) Phenolphthalein

Phenolphthalein is colourless in acid (< pH 8.3) and red in base (> pH 10).

This is a narrow pH range, so phenolphthalein is good for titrating acids with strong bases..

However, it can't distinguish between acids and weakly basic solutions.

It would be colourless in a strongly acid solution with pH =1 and in a basic solution with pH = 8.

(c) Other indicators

Other acid-base indicators have the general limitations as phenolphthalein. Most of them have a small pH range, so they are useful in acid-base titrations.

The only one that could serve as a general acid-base indicator is bromothymol blue, which has a pH range of 6.0 to 7.6.

5 0

3 years ago