What volume of a 1.3 M solution of Na2CO3 can be made from 800 ml. of a 4.9

Why is unit of pressure called a derived unit ?? 2) how do you measure the volume of milk?

trasher [3.6K]

1. Unit of pressure called a derived unit because it is a combination of base units (kg·m^-1·s^·2).

2. We measure the volume of milk by a instrument called Milk Lactometer.

4 0

3 years ago

Deep sea divers use a mixture of helium and oxygen to breathe. Assume that a diver is going to a depth of 150 feet where the tot

Svetlanka [38]

Answer:

4.525% is the percentage by volume of oxygen in the gas mixture.

Explanation:

Total pressure of the mixture = p = 4.42 atm

Partial pressure of the oxygen = $p_1=0.20 atm$

Partial pressure of the helium = $p_2$

$p_1=p\times \chi_1$ (Dalton law of partial pressure)

$0.20 atm=4.42 atm\times \chi_1$

$\chi_1=\frac{0.20 atm}{4.42 atm}=0.04525$

$\chi_2=1-\chi_1=1-0.04525=0.95475$

$chi_1+chi_2=1$

$n_1=0.04525 mol,n_2=0.95475 mol$

According Avogadro law:

$Moles\propto Volume$ (At temperature and pressure)

Volume occupied by oxygen gas = $V_1$

Total moles of gases = n = 1 mol

Total Volume of the gases = V

$\frac{n_1}{V_1}=\frac{n}{V}$

$\frac{V_1}{V}=\frac{n_1}{n}=\frac{0.04525 mol}{1 mol}$

Percent by volume of oxygen in the gas mixture:

$\frac{V_1}{V}\times 100=\frac{0.04525 mol}{1 mol}\times 100=4.525\%$

6 0

3 years ago

The image compares the arrangement of electrons in two different neutral atoms.

jekas [21]

Answer:

Option b. Atom P has an estimated Zeff of 7 and is therefore to the right of Atom Q, which has a Zeff of 6.

Explanation:

Please, find attached the figures of both atom Q and atom P corresponding to this question.

The features of atom Q are:

Each black sphere represents an electron

In total this atom has 8 electrons: 2 in the inner shell and 6 in the outermost shell.

Since it is assumed that the atom is neutral, it has 8 protons: one positive charge of a proton balances one negative charge of an electron. Thus, the atomic number of this atom is 8.

Since only two shells are ocuppied, you can assert that the atom belongs to the period 2 (which is confirmed looking into a periodic table with the atomic number 8).

Zeff is the effective nuclear charge of the atom. It accounts for the net positive charge the valence electrons experience. And may, in a very roughly way, be estimated as the number of protons less the number of electrons in the inner shells. Thus, for this atom, an estimated Z eff = 8 - 2 = 6.

The features of atom P are:

Again, each black sphere represents an electron

In total this atom has 9 electrons: 2 in the inner shell and 7 in the outermost shell.

Since it is assumed that the atom is neutral, it has 9 protons.

The atomic number of this atom is 9.

Using the same reasoning used for atom Q, this atom is also in the period 2.

Estimated Z eff = 9 - 2 = 7.

Then, since atom P has a greater Z eff than atom Q (an estimated Zeff of 7 for atom P against an estimated Z eff of 6 for atom Q), and both atoms are in the same period, you can affirm that atom P has a greater atomic number and is therefore to the right of atom Q.

8 0

3 years ago

The chemical equation, Cr + Fe(NO3)2 → Fe + Cr(NO3)3, is an example of which type of reaction?

Angelina_Jolie [31]

Answer:

Redox type

Explanation:

The reaction is:

2Cr + 3Fe(NO₃)₂ → 2Fe + 2Cr(NO₃)₃

2 moles of chromium can react to 3 moles of iron (II) nitrate in order to produce 2 moles of iron and 2 moles of chromium nitrate.

If we see oxidation state, we see that chromium changes from 0 to +3

Iron changed the oxidation state from +2 to 0

Remember that elements at ground state has 0, as oxidation state.

Iron is being reduced while chromium is oxidized. Then, the half reactions are:

Fe²⁺ + 2e⁻ ⇄ Fe (Reduction)

Cr ⇄ Cr³⁺ + 3e⁻ (Oxidation)

When an element is being reduced, while another is being oxidized, we are in prescence of a redox reaction.

8 0

3 years ago

Write two reactions showing nascent Hydrogen is more reactive than molecular Hydrogen.

ratelena [41]

Answer:

1.) Nascent Hydrogen has more energy than Molecular Hydrogen.

2.) Nascent Hydrogen is are more on the side of atomic and since atoms are more active than molecules, Nascent Hydrogen becomes more reactive.

4 0

3 years ago