Below is a diagram of an atom. What is the atomic number of this atom?

Classify the following processes as exothermic or endothermic: (b) boiling of water;

malfutka [58]

(b) boiling of water is an endothermic process.

A response that is chemical in nature and is characterized with the aid of the release of power in the shape of warmth or light is referred to as an exothermic response. Matching a mild using a matchstick is one example of this kind of reaction where the discharge is inside the shape of each warmness and light.

Endothermic reactions are chemical reactions wherein the reactants soak up warmness electricity from the environment to shape products. those reactions decrease the temperature of their surrounding place, thereby growing a cooling impact.

Learn more about exothermic here:- brainly.com/question/2924714

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DISCLAIMER:- Your question is incomplete , see full question below:-

Classify the following processes as exothermic or endothermic:

(a) freezing of water.

(b) boiling of water.

(c) digestion of food.

(d) a person running.

(e) a person growing.

(f) wood being chopped.

(g) heating with a furnace.

5 0

1 year ago

An atom has a diameter of 2.50 Å and the nucleus of that atom has a diameter of 9.00×10−5 Å . Determine the fraction of the volu

chubhunter [2.5K]

Answer:

The fraction of the volume of the atom that is taken up by the nucleus is $4.6656\times 10^{-14}$ .

The density of a proton is $6.278\times 10^{14} g/cm^3$ .

Explanation:

Diameter of the atom ,d = 2.50 Å

Radius of the atom ,r = 0.5 d=0.5 × 2.50 Å = 1.25Å

Volume of the sphere= $\frac{4}{3}\pi r^3$

Volume of atom = V

$V=\frac{4}{3}\pi r^3$ ..[1]

Diameter of the nucleus ,d' = $9.00\times 10^{-5}\AA$

Radius of the nucleus ,r' = 0.5 d'= $0.5\times 9.00\times 10^{-5}\AA=4.5\times 10^{-5}\AA$

Volume of nucleus = V'

$V=\frac{4}{3}\pi r'^3$ ..[2]

Dividing [2] by [1]

$\frac{V'}{V}=\frac{\frac{4}{3}\pi r'^3}{\frac{4}{3}\pi r^3}$

$=\frac{r'^3}{r^3}=\frac{(4.5\times 10^{-5}\AA)^3}{(1.25 \AA)^3}$

$\frac{V'}{V}=4.6656\times 10^{-14}$

The fraction of the volume of the atom that is taken up by the nucleus is $4.6656\times 10^{-14}$ .

Diameter of the proton ,d = $1.72\times 10^{-15} m = 1.72\times 10^{-13} cm$

1 m = 100 cm

Radius of the proton,r = 0.5 d= $0.5\times 1.72\times 10^{-13} cm=8.6\times 10^{-14} cm$

Volume of the sphere= $\frac{4}{3}\pi r^3$

Volume of atom = V

$V=\frac{4}{3}\times 3.14\times (8.6\times 10^{-14} cm)^3=2.664\times 10^{-39}cm^3$

Mass of proton, m = 1.0073 amu = $1.0073\times 1.66054\times 10^{-24} g$

$1 amu = 1.66054\times 10^{-24} g$

Density of the proton : d

$d=\frac{m}{V}=\frac{1.0073\times 1.66054\times 10^{-24} g}{2.664\times 10^{-39}cm^3}=6.278\times 10^{14} g/cm^3$

The density of a proton is $6.278\times 10^{14} g/cm^3$ .

5 0

4 years ago

What was one main point of Dalton’s atomic theory?

Cerrena [4.2K]

The answer to this question is C, I hope this helps you!

8 0

4 years ago

Name 20 chemical changes in our daily environment

ehidna [41]

Answer:

chemical reactions In our daily environment are

1) Cooking food

2) Photosynthesis

3) rusting

4) painting

5) respiration

6) combustion

7) Electrochemistry (including chemical batteries)

8)Digestion

9)Soap and detergent reactions

10)Acid-base reactions

11) fermentation

12) oxidation

13 ) burning of paper

14) riping of fruits

15) frying egg

16) souring of milk

17) baking

18) heating sugar

19) burning wood

20) rising bread

8 0

2 years ago

The half-life of radon-222 is 3.82 days. If a sample of gas contains 4.38 μg of radon-222, how much will remain in the ample aft

LekaFEV [45]

Answer:

$0.28 \mu g$

Explanation:

We can write the amount of mass of radon-222 left after a time t by using the equation:

$m(t) = m_0 (\frac{1}{2})^{t/t_{1/2}}$

where

$m_0 = 4.38 \mu g$ is the initial mass

t is the time

$t_{1/2} = 3.82 d$ is the half-life

Substituting t = 15.2 d in the formula, we find

$m(15.2 d) = (4.38 \mu g) (\frac{1}{2})^{15.2d/3.82 d}=0.28 \mu g$

3 0

4 years ago