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3 years ago

PLEASEEEEEEEEEEE HELP WILL MARK BRAINLIEST!!!!!!!!!!!

Chemistry

2 answers:

slamgirl [31]3 years ago

7 0

Answer:

The correct statement is that Example A describes a chemical change and Example B describes a physical change.

Explanation:

In example A we have a chemical change because the use of soaps and detergents implies a chemical reaction called saponification due to the soap molecules has a double component the first part of a soap is called hydrophilic and the second part is called hydrophobic. so, when the soap molecules interact with the oil molecules in water the hydrophilic part will be bonded with water and the hydrophobic part will be bonded with the oil. This new bondings are called micelles and the formations of micelles by new bonds it is a chemical change.
In example B there is a physical change because the water in a Bowl is evaporated. it means that at higher temperatures the molecules of water pass from the liquid state of the matter to the gas state. This physical change happens after the water molecules reach enough energy able to broke surface tension in liquid water. This energy is obtained thanks to the increasing of temperature, and the temperature needed to achieve this change from liquid to gas is called boiling point.

Sidana [21]3 years ago

3 0

Example A describes a chemical change and Example B describes a physical change.

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The work function of an element is the energy required to remove an electron from the surface of the solid. The work function fo

uranmaximum [27]

Answer:

λ = 2.38 × 10^(-7) m

Explanation:

We are given the work function for palladium as 503.7 kJ/mol.

Now let's convert this to KJ/electron.

We know from avogadro's number that;

1 mole of electron = 6.022 × 10^(23) electrons

Thus,

503.7 kJ/mol = 503.7 × 1/(6.022 × 10^(23)) = 8.364 × 10^(-22) KJ/electron = 8.364 × 10^(-19) J/electron

Formula for energy of a photon is;

E = hv

Where;

h is Planck's constant = 6.626 × 10^(-34) J.s

v is velocity

Now, v = c/λ

Where;

c is speed of light = 3 × 10^(8) m/s

λ is wavelength of light.

Thus;

E = hc/λ

Making λ the subject, we have;

λ = hc/E

λ = (6.626 × 10^(-34) × 3 × 10^(8))/(8.364 × 10^(-19))

λ = 2.38 × 10^(-7) m

4 0

2 years ago

What volume of stock solution and water must you add to prepare 36.25ml of a 1.25M solution

Serjik [45]

Given :

Number of moles , n = 36.25 mol .

Molarity , M = 1.25 M .

To Find :

The volume of water required .

Solution :

Moarity is given by :

$M=\dfrac{n}{V}$

So , $V=\dfrac{n}{M}$

Here , n is number of moles and M is molarity .

Putting all values in above equation , we get :

$V=\dfrac{36.25}{1.25}\\\\V=29\ L$

Therefore , volume of water required is 29 L .

5 0

3 years ago

Write a balanced overall reaction from these unbalanced half-reactions. ln->ln3+ cd2+->cd

DochEvi [55]

Oxidation reaction
In ---> In³⁺ + 3e ---1)
reduction reaction
Cd²⁺ + 2e ---> Cd ---2)
when balancing the reactions, electrons have to be balanced. to balance the electrons multiple 1st reaction by 2 and 2nd reaction by 3
1) x 2
2) x 3
2In ---> 2In³⁺ + 6e
3Cd²⁺ + 6e ---> 3Cd
add the 2 equations to obtain the overall reaction

2In + 3Cd²⁺ ---> 2In³⁺ + 3Cd

5 0

3 years ago

Help asap

alisha [4.7K]

Answer: Option (b) is the correct answer.

Explanation:

It is known that metals are the species which readily lose an electron and tend to attain a positive charge.

For example, atomic number of sodium is 11 and its is an alkali metal. It electronic distribution is 2, 8, 1.

And, in order to attain stability it readily loses an electron and thus it become $Na^{+}$ ion.

Also, it is known that species which tend to transfer or donate their valence electrons to other atoms tend to form ionic bond and the compound formed is known as ionic compound.

Therefore, we can conclude that the statement metal atoms held together by ionic bonds best describes a metal solid.

4 0

3 years ago

At 700 K, the reaction2SO2(g) + O2(g) 2SO3(g)has the equilibrium constant Kc = 4.3 x 106, and the following concentrations are p

dedylja [7]

Explanation:

The given reaction is as follows.

$2SO_{2} + O_{2}(g) \rightarrow 2SO_{3}(g)$