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3 years ago

What is radio isotopes?

2 answers:

7 0

Radioactive isotope, also called radioisotope, radionuclide, or radioactive nuclide, any of several species of the same chemical element with different masses whose nuclei are unstable and dissipate excess energy by spontaneously emitting radiation in the form of alpha, beta, and gamma rays.

Julli [10]3 years ago

4 0

Any of the same chemical element with different masses whose nuclei are unstable and gets energy by emitting radiation in the form of alpha, beta, and gamma rays.

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A chemistry student weighs out of hypochlorous acid into a volumetric flask and dilutes to the mark with distilled water. He pla

riadik2000 [5.3K]

Answer:

Volume of NaOH, aka V2 = 6.32 mL to 3 sig. fig.

A chemistry student weighs out 0.0941 g of hypochlorous acid (HClo) into a 250. ml. volumetric flask and dilutes to the mark with distilled water. He plans to titrate the acid with 0.2000 M NaOH solution. Calculate the volume of NaOH solution the student will need to add to reach the equivalence point. Round your answer to 3 significant digits mL.

Explanation:

1 mole HClO = 74.44g

0.0941g = $\frac{0.0941}{74.44}$ = 0.00126 moles

Concentration = no. of moles/volume in L

Hence, Concentration of HClO = 0.00126/ 0.250L

= 0.005M.

C1V1 =C2V2

0.005 × 250 mL = 0.2 × V2

Volume of NaOH, aka V2 = 6.32 mL to 3 sig. fig.

3 0

3 years ago

Consider the reaction directly below and answer parts a and b. C6H4(OH)2 (l) + H2O2 (l) à C6H4O2 (l) + 2 H2O (l)

dedylja [7]

Answer:

a. -206,4kJ

b. Surroundings will gain heat.

c. -115kJ are given off.

Explanation:

It is possible to obtain ΔH of a reaction using Hess's law that consist in sum the different ΔH's of other reactions until obtain the reaction you need.

Using:

(1) C₆H₄(OH)₂(l) → C₆H₄O₂(l) + H₂(g) ΔH: +177.4 kJ

(2) H₂(g) + O₂(g) → H₂O₂ (l) ΔH: -187.8 kJ

(3) H₂(g) + 1/2O₂(g) → H₂O(l) ΔH: -285.8 kJ

It is possible to obtain:

C₆H₄(OH)₂(l) + H₂O₂(l) → C₆H₄O₂(l) + 2H₂O(l)

From (1)-(2)+2×(3). That is:

(1) C₆H₄(OH)₂(l) → C₆H₄O₂(l) + H₂(g) ΔH: +177.4 kJ

-(2) H₂O₂(l) → H₂(g) + O₂(g) ΔH: +187.8 kJ

2x(3) 2H₂(g) + O₂(g) → 2H₂O(l) ΔH: 2×-285.8 kJ

The ΔH you obtain is:

+177,4kJ + 187,8kJ - 2×285.8 kJ = -206,4kJ

b. When ΔH of a reaction is <0, the reaction is exothermic, that means that the reaction produce heat and the surroundings will gain this heat.

c. 20,0g of H₂O are:

20,0g× $\frac{1mol}{18,01g}$ = 1,11 mol H₂O

As 2 moles of H₂O are produced when -206,4kJ are given off, when 1,11mol of H₂O are produced, there are given off:

1,11mol H₂O× $\frac{-206,4kJ}{2mol}$ = -115kJ

I hope it helps!

8 0

3 years ago

A firework exploding is an example of a (4 points) physical change chemical change phase change nuclear change

Irina-Kira [14]

A firework exploding is a chemical change as soon as you light the fuse the combustion reacts with the gunpowder.

I hope this helps, good luck!!!!

5 0

3 years ago

An atom has 20 electrons. Find out

Yanka [14]

Answer:

it's atomic number is 5 and total number is 10

8 0

3 years ago

What are the harmful effects of water pollution

maksim [4K]

Answer:

- Reduced biodiversity

- Health problems from drinking the water

- Diseases

8 0

3 years ago