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1 year ago

Is each of the following statements true or false? Correct any that are false.

1 answer:

5 0

True, A mole of one substance has the same number of atoms as a mole of any other substance.

Mole, also spelled mol, in chemistry, a standard scientific unit for measuring large quantities of very small entities such as atoms, molecules, or other specified particles.

The mole designates an extremely large number of units, 6.02214076 × $10^{23}$ . The General Conference on Weights and Measures defined the mole as this number for the International System of Units (SI) effective from May 20, 2019. The mole was previously defined as the number of atoms determined experimentally to be found in 12 grams of carbon-12.

The number of units in a mole also bears the name Avogadro’s number, or Avogadro’s constant, in honour of the Italian physicist Amedeo Avogadro (1776–1856). Avogadro proposed that equal volumes of gases under the same conditions contain the same number of molecules, a hypothesis that proved useful in determining atomic and molecular weights and which led to the concept of the mole.

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Acids reacts with base and produces salt and water represent it in the form of chemical equation

tatiyna

Answer:

HCl+ NaoH- Nacl+H2O

Explanation:

base react with acid

3 0

3 years ago

A mixture of gases with a pressure of 800.0 mm hg contains 60% nitrogen and 40% oxygen by volume. What is the partial pressure o

larisa86 [58]

Answer:

The partial pressure of oxygen in the mixture is 320.0 mm Hg

Explanation:

1) Take a base of 100 liters of mixture:

N: 60% × 100 liter = 60 liter

O: 40 % × 100 liter = 40 liter.

2) Volume fraction:

At constant pressure and temperature, the volume of a gas is proportional to the number of molecules.

Then, the mole ratio is equal to the volume ratio. Callin n₁ and n₂, the number of moles of nitrogen and oxygen, respectively, and V₁, V₂ the volume of the respective gases you can set the proportion:

V₁ / V₂ = n₁ / n₂

That means that the mole ratio is equal to the volume ratio, and the mole fraction is equal to the volume fraction.

Then, since the law of partial pressures of gases states that the partial pressure of each gas is equal to the mole fraction of the gas multiplied by the total pressure, you can draw the conclusion that the partial pressure of each gas is equal to the volume fraction of the gas in the mixture multiplied by the total pressure.

Then calculate the volume fractions:

Volume fraction of a gas = volume of the gas / volume of the mixture

N: 60 liter / 100 liter = 0.6 liter

V: 40 liter / 100 liter = 0.4 liter

3) Partial pressures:

These are the final calculations and results:

Partial pressure = volume fraction × total pressure

Partial pressure of N = 0.6 × 800.0 mm Hg = 480.0 mm Hg

Partial pressure of O = 0.4 × 800.0 mm Hg = 320.0 mm Hg

8 0

3 years ago

An oxide of aluminum contains 0.545 g of Al and 0.485 g of O. Find the empirical formula

uysha [10]

Answer:

The answer is: Al2O3

Explanation:

The data they give us is:

0.545 gr Al

0.485 gr O.

To find the empirical formula without knowing the grams of the compound, we find it per mole:

0.545 g Al * 1 mol Al / 27 g Al = 0.02 mol Al

0.485 g O * 1 mol O / 16 g O = 0.03 mol O

Then we must divide the results obtained by the lowest result, which in this case is 0.02:

0.02 mol Al / 0.02 = 1 Al

0.03 mol O / 0.02 = 1.5 O

Since both numbers have to give an integer, multiply by 2 until both remain integers:

1Al * 2 = 2Al

1.5O * 2 = 3O

Now the answer is given correctly:

Al2O3

8 0

3 years ago

What is the expected mass (in kg) of a 10 over 5 B isotope? 1 proton = 1.6726 × 10-27 kg 1 neutron = 1.6749 × 10-27 kg A.1.67 ×

Ira Lisetskai [31]

$^{10}_5 B$
An atom of this isotope contains 5 protons and 10-5=5 neutrons.

$5 \times 1.6726 \times 10^{-27} + 5 \times 1.6749 \times 10^{-27} = \\
8.363 \times 10^{-27} + 8.3745 \times 10^{-27}= \\
16.7375 \times 10^{-27}= \\
1.67375 \times 10^{-26} \approx \\
1.67 \times 10^{-26}$

The answer is A. 1.67 × 10⁻²⁶ kg.

8 0

3 years ago

a doctor's order is 0.125 g of ampicillin. the liquid suspension on hand contains 250 mg/5.0 ml. how many milliliters of the sus

disa [49]

0.125 g=(0.125 g)(1000 mg/1g)=125 mg.

Then, we need 125 mg of ampicillin.
5 ml of liquid suspension contains 250 mg of ampicilling , therefore:

5 ml----------------250 mg of ampicilling
x--------------------125 mg of ampicilling

x=(5 ml * 125 mg of ampicilling) / 250 mg of ampicilling=2.5 ml

Answer: we require 2.5 ml

5 0

3 years ago

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