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3 years ago

Helpppp fasttttttttttttttt Choose the best word to complete the sentence.

Chemistry

1 answer:

Lapatulllka [165]3 years ago

5 0

Answer:

equilateral (B)

Explanation:

it is the only word which relates to triangles and their shape - plus, its logical and makes sense.

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Which of the following substances

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A, Saline NaCI and H,0

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3 years ago

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Where else has lead contamination of water occurred in recent history?

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Flint, Michigan newldo

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3 years ago

Calculate the partial pressure of each gas and the total pressure if the temperature of the gas is 21 ∘C∘C. Express the pressure

Volgvan

The question is incomplete, complete question is ;

A deep-sea diver uses a gas cylinder with a volume of 10.0 L and a content of 51.8 g of $O_2$ and 33.1 g of He. Calculate the partial pressure of each gas and the total pressure if the temperature of the gas is 21°C.Express the pressures in atmospheres to three significant digits separated by commas.

Answer:

Partial pressure of the oxygen gas is 3.91 atm.

Partial pressure of the helium gas is 20.0 atm

Total pressure of the gases is 24.0 atm

Explanation:

Moles of oxygen gas = $n_1=\frac{51.8}{32 g/mol}=1.619 mol$

Moles of helium gas = $n_2=\frac{33.1 g}{4 g/mol}=8.275 mol$

Total moles of gas = $n_1+n_2=(1.619 +8.275 ) mole=9.894 mol$

Volume of the cylinder = V = 10.0 L

Total pressure in the cylinder = P = ?

Temperature of the gas in cylinder = T = 21°C = 21 + 273 K = 294 K

PV = nRT ( ideal gas equation )

$P=\frac{nRT}{V}$

$=\frac{9.894 mol\times 0.0821 atm L/mol K\times 294 K}{10.0 L}$

P = 23.88 atm ≈ 23.9

Partial pressure of the individual gas will be determined by the help of Dalton's law:

partial pressure = Total pressure × mole fraction of gas

Partial pressure of the oxygen gas

$p_{1}=P\times \chi_{1}=P\times \frac{n_1}{n_1+n_2}$

$p_1=23.88 atm\times \frac{1.619 mol}{9.894 mol}=3.91 atm$

Partial pressure of the helium gas

$p_{2}=P\times \chi_{2}=P\times \frac{n_2}{n_1+n_2}$

$p_2=23.88 atm\times \frac{8.275 mol}{9.894 mol}=19.97 atm\approx 20.0 atm$

6 0

3 years ago

Why don't I need prefixes to designate the number of each type of element when naming ionic compounds?

scoray [572]

We use prefixes in ionic compounds Don't use numeric prefixes like mono, di, tri, etc. when naming ionic compounds - they are used only to denote covalent molecular compounds.

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2 years ago

What happens to isotopes that are unstable?

Lesechka [4]

<u>Explanation:</u>

Isotopes are defined as the chemical species of the same element which differs in the number of neutrons. The isotopes which are unstable are known as radioactive isotope. A radioactive (unstable )isotope can undergo 3 decay process:

1. Alpha Decay: In this decay process, a larger nuclei decays into smaller nuclei by releasing alpha particle. The particle released has a charge of +2 and a mass of 4 units.

$_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}Y+_2^4\alpha$

2. Beta-minus decay: In this decay process, a neutron gets converted into a proton and an electron. the particle released during this process is a beta-particle.

$_Z^A\textrm{X}\rightarrow _{Z+1}^A\textrm{Y}+_{-1}^0\beta$

3. Beta-plus decay: In this decay process, a protons gets converted into a neutron and electron-neutrino particle. The particle released during this process is a positron particle.

$_Z^A\textrm{X}\rightarrow _{Z-1}^A\textrm{Y}+_{+1}^0\beta$

Isotopes which are unstable in nature can undergo these 3 decay processes.

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3 years ago