Most of the volume of an atom is occupied by the ?

Which statements accurately describe soap? Select one or more:

tia_tia [17]

Answer:

A. Soaps react with ions in hard water to create a precipitate.

B. Soaps are both hydrophobic and hydrophilic.

D. Soaps should be weakly alkaline in solution.

Explanation:

A. Hard water contains <u>magnesium and calcium minerals</u> like calcium and magnesium carbonates, sulfates and bicarbonates. As soon as these minerals come in contact with soap their ions like Mg²⁺ & Ca²⁺ form precipitates.

B. Soap are both hydrophilic and hydrophobic. They reason why they exhibit both the properties is really important for their functionality. The hydrophobic part of soap makes interaction with oil/dust particles while the hydrophilic part makes interaction with water. When the cloth is rinsed the dirt/soap particles are removed from the dirty clothes thereby making them clean.

C. Soaps have alkaline pH i.e. more than 7 that is why they have bitter taste.

5 0

3 years ago

Calculate the masses of oxygen and nitrogen that are dissolved in of aqueous solution in equilibrium with air at 25 °C and 760 T

shtirl [24]

Explanation:

Let us assume that the volume of given aqueous solution is 7.5 L.

Therefore, according to Henry's law, the relation between concentration and pressure is as follows.

C = $\frac{P}{K_{h}}$

where, pressure (P) = 760 torr = 1 atm

According to Henry's law, constants for gases in water at $25^{o}C$ are as follows.

$p(O_{2})$ = 0.21 atm = 0.21 bar

$p(N_{2})$ = 0.78 atm = 0.78 bar

$K_{h}$ for $O_{2}$ = $7.9 \times 10^{2} bar/mol$

$K_{h}$ for $N_{2}$ = $1.6 \times 10^{3} bar /mol$

Since, 21% oxygen is present in air so, its mass will be 0.21 g. Similarly, 78% nitrogen means the mass of nitrogen is 0.78 g.

Therefore, concebtrations will be calculated as follows.

$C(O_{2}) = \frac{0.21}{7.9 \times 10^{2}} = 2.66 \times 10^-4 mol/L$

$C(N_2) = \frac{0.78}{1.6 \times 10^3} = 4.875 \times 10^-4 mol/L$

Now, we will calculate the number of moles as follows.

$n(O_{2}) = 7.5 \times 2.66 \times 10^-4 = 1.995 \times 10^-3$ mol

$n(N_2) = 7.5 \times 4.875 \times 10^-4 = 3.66 \times 10^-3$ mol

As the molar mass of $O_2$ = 32 g/mol

Hence, mass of oxygen will be as follows.

Mass of $O_2 = 32 \times 1.995 \times 10^-3 \times 1000$

= 63.84 mg

As the molar mass of $N_{2}$ = 28

Mass of $N_{2} = 28 \times 3.66 \times 10^-3$ = 102.5 mg

Thus, we can conclude that mass of oxygen is 63.84 mg and nitrogen is 102.5 mg.

5 0

4 years ago

Read 2 more answers

The ka of hf is 6.8 x 10-4. what is the ph of a 0.35 m solution of hf?

damaskus [11]

When the reaction equation is:

HF ↔ H+ + F-

and when the Ka expression
= concentration of products/concentration of reactions

so, Ka = [H+][F-]/[HF]

when we assume:

[H+] = [F-] = X

and [HF] = 0.35 - X

So, by substitution:

6.8 x 10^-4 = X^2 / (0.35 - X) by solving for X

∴ X = 0.015 M

∴[H+] = X = 0.015

when PH = -㏒[H+]

∴PH = -㏒0.015

= 1.8

6 0

3 years ago

One mole of calcium ions has the same number of representative particles as which of the following? one mole of calcium nuclei o

Kruka [31]

One mole is always the same number: 6.02 * 10^ 23.

So, one mole of cars = 6.02 * 10 ^23 cars; one mole of pencils = 6.02 * 10^23 pencils; one mole of atoms = 6.02 * 10^23 atoms; one mole of molecules = 6.02 * 10^23 molecules.

So, all the options are correct: one mole of calcium ions has 6.02 * 10^23 representative particles, such as one mole of calcium nuclei and one of calcium atoms.

3 0

3 years ago

What type(s) of bonding would be expected for each of the following materials: brass (a copper-zinc alloy), rubber, barium sulfi

mr_godi [17]

The force of attraction that results in holding of atoms or ions together in a molecule or crystal is said be bonding. Bond formation can take place by either attraction or transfer of electrons. There are single, double, and triple bonds. There are many types of bonding namely:

Covalent (sharing of electrons takes place).

Ionic (transfer of electrons takes place).

Metallic (ionized atoms of metals and the sea of electrons around them).

Brass (a copper-zinc alloy)

Brass is an alloy of metal that is copper and zinc. Hence, the metallic bonding is present in the brass.

Rubber

It is a polymer whose monomer unit is isoprene, which is a covalent compound. The isoprene units are attached in repeated units to form rubber by covalent bonding.

Barium sulfide ( $BaS$ )

Due to the large electronegativity difference between barium and sulfur, barium sulfide is an ionic compound. Thus, ionic bonding is present in barium sulfide.

Solid xenon

Only xenon atoms are present in solid xenon which are interacted by weak Van der Waal's interactions.

Bronze

Bronze is an alloy of metal that is copper and tin. Hence, the metallic bonding is present in the brass.

Nylon

It is a polymer whose monomer unit is caprolactam, which is a covalent compound. The caprolactam units are attached in repeated units to form nylon by covalent bonding.

Aluminum phosphide ( $AlP$ )

Aluminum phosphide is a covalent compound and thus involves covalent bonding.

7 0

3 years ago