Ask question

Ask question

All categories

adelina 88 [10]

3 years ago

9

Which of the following is true about chemical reactions. A. they are accompanied by changes in energy. B. they form new substanc

es with new properties. C. both A & B
D.neither A nor B

1 answer:

Ilia_Sergeevich [38]3 years ago

7 0

The correct answer should be option C. hope this helps

You might be interested in

If you can continue to add more solute to a solution, the solution is said to be ____________________

Savatey [412]

Answer:

Unsaturated

Explanation:

In order to successfully answer this question, we need to think about the solubility of solutes in specific solvents, typically water.

A solution is considered to be unsaturated if at a given temperature and volume of water we may still add more solute and it will dissolve;
A solution is considered to be saturated if at a given temperature and volume of water we have a maximum amount of solute dissolved and trying to add more solute results in undissolved crystals that can be seen in the solution;
A solution is considered to be oversaturated (or supersaturated) i at a given temperature and volume of water we exceeded the maximum amount of a solute that could possibly dissolve.

In this case, if we can continue to add more solute to a solution and the solute dissolves, we may state that we are still at a point in which we have an unsaturated solution.

4 0

3 years ago

Read 2 more answers

What are 3 characteristics of cnidarians?

patriot [66]

Tentacles with stinging cells, 2 body layers (ectoderm & endoderm), radially symmetric

5 0

3 years 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

3 years ago

Where is a product found at the beginning or end of a chemical reaction?

olya-2409 [2.1K]

A reaction is when two or more pure substances combine with each other to form another identity of pure substances. In general from, it is written as:

A + B → C + D

The substances A and B are the reactants, while the substances C and D are the products. Therefore, in a reaction, the products are found at the end or right side of the reaction.

3 0

3 years ago

Which of the molecules below must be shown with resonance structures?

timama [110]

It seems that you have missed the given options for this question, but anyway, the correct answer is NONE OF THE ABOVE. None of the molecules given must be shown with resonance structures. A resonance structure is defined as the way or presenting <span>delocalized electrons within certain molecules or polyatomic ions. This bonding cannot be expressed by one single Lewis </span><span>structure. Hope this answer helps.</span>

8 0

3 years ago