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2 years ago

What mass of copper is required to replace silver from 4.00g of silver nitrate dissolved in water?

1 answer:

3 0

The balanced chemical reaction is written as:

<span>Cu +2AgNO3 → Cu(NO3)2 + 2Ag
</span>
We are given the amount of silver nitrate to be used for the reaction. This value will be the starting point of our calculations. It is as follows:

4.00 g AgNO3 ( 1 mol / 169.87 g ) ( 1 mol Cu / 2 mol AgNO3 ) ( 63.456 g / 1 mol ) = 0.747 g Cu

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A 60.2-ml sample of hg (density = 13.6 g/ml) contains how many atoms of hg?

Over [174]

Density is calculated using the following rule:
density = mass / volume
therefore:
mass = density * volume
mass of Hg = 13.6 * 60.2 = 818.72 grams

From the periodic table:
molar mass of Hg = 200.59 grams

number of moles = mass / molar mass
number of moles of Hg = 818.72 / 200.59 = 4.08 moles

each mole contains Avogadro's number of atoms.
Therefore,
number of atoms in the given sample = 4.08 * 6.022 * 10^23
= 2.456976 * 10^24 atoms

6 0

2 years ago

1) How many aluminum atoms are there in 3.50 grams of Al2O3?

drek231 [11]

Answer:

Aluminium atoms = 4.13 *10^22 aluminium atoms

The correct answer is E

Explanation:

Step 1: Data given

Mass of Al2O3 = 3.50 grams

Molar mass of Al2O3 = 101.96 g/mol

Number of Avogadro = 6.022 * 10^23 /mol

Step 2: Calculate moles Al2O3

Moles Al2O3 = mass Al2O3 / molar mass Al2O3

Moles Al2O3 = 3.50 grams / 101.96 g/mol

Moles Al2O3 = 0.0343 moles

Step 3: Calculate moles Aluminium

In 1 mol Al2O3 we have 2 moles Al

in 0.0343 moles Al2O3 we have 2*0.0343 = 0.0686 moles Al

Step 4: Calculate aluminium atoms

Aluminium atoms = moles aluminium * Number of Avogadro

Aluminium atoms = 0.0686 * 6.022 * 10^23

Aluminium atoms = 4.13 *10^22 aluminium atoms

The correct answer is E

3 0

2 years ago

When heating a flammable or volatile solvent for a recrystallization, which of these statements are correct? More than one answe

otez555 [7]

Explanation:

A volatile substance is defined as the substance which can easily evaporate into the atmosphere due to weak intermolecular forces present within its molecules.

Whereas a flammable substance is defined as a substance which is able to catch fire easily when it comes in contact with flame.

Hence, when we heat a flammable or volatile solvent for a recrystallization then it should be kept in mind that should heat the solvent in a stoppered flask to keep vapor away from any open flames so that it won't catch fire.

And, you should ensure that no one else is using an open flame near your experiment.

Thus, we can conclude that following statements are correct:

You should heat the solvent in a stoppered flask to keep vapor away from any open flames.

You should ensure that no one else is using an open flame near your experiment.

3 0

2 years ago

What is the amount of heat released when 25g of water cools 12.5 degrees C ?

Over [174]

Water can't cool at a single temperature. It must start at a higher temperature, and drop to a lower temperature in order to cool. Unless we know the other temperature, there is no way to calculate the amount of thermal energy released.

4 0

2 years ago

PLS HELP ASAP, WILL GIVE 100 POINTS.

Ivan

Answer: values of the quantum numbers: -6,-5,-4,-3,-2,-1,0,1,2,3,4,5,6

location of the electron: In the 7th energy level away from the nucleus.

Explanation:

From the description of the problem, the magnetic number is given is as -6,-5,-4,-3,-2,-1,0,1,2,3,4,5,6 and the electron is located in the 7th energy level away from the nucleus. Basically, the problem is testing for the understanding of the principal quantum numbers which gives the location of electrons and the magnetic quantum number that shows the spatial orientation of the orbitals.

The orbital designation of the describe electron is 7d

Magnetic quantum number is limited by the azimuthal quantum number which is the quantum number describing the possible shapes. The azimuthal is given as L= n-1. "n" is the principal quantum number which is 7. Therefore L is 6 and the magnetic quantum numbers are -6,-5,-4,-3,-2,-1,0,1,2,3,4,5,6

The position of the electron is given by the principal quantum number which represents the main energy level in which the orbital is located or the average distance from the nucleus.

Got it from quasarJose

Hope it helps

5 0

2 years ago