What are 2 instruments used to test for conductivity

To gain an idea as to how many atoms are in a gram or so of copper, use the larger balance

anygoal [31]

Answer:

Explanation:

To solve this problem, we must understand the relationship between mass of a substance and the number of atoms.

Atoms are the smallest indivisible particles of any matter. A substance can be made up of several number of atoms in their space.

The mass of any substance is a function of the amount of atoms its contains.

The mass of a substance is related in chemistry to the amount of atoms its contains using the parameter called the number of moles.

A mole is the amount of substance that contains the Avogadro's number of particles. This number is 6.02 x 10²³ particles. The particles here can be protons, neutrons, electrons, atoms e.t.c.

Now,

Number of moles = $\frac{mass}{molar mass}$

Molar mass of copper = 63.6g/mole

Number of moles = $\frac{2}{63.6}$ = 0.03mole

Since 1 mole of a substance contains 6.02 x 10²³atoms

0.03 mole of copper will contain 0.03 x 6.02 x 10²³atoms

= 1.89 x 10²² atoms

He needs to add 1.89 x 10²² atoms to make 2g of the sample.

7 0

3 years ago

How molecules of N2 gas can be present in a 2.5 L flask at 50°C and 650 mmHg?

ratelena [41]

Answer:

0.482 ×10²³ molecules

Explanation:

Given data:

Volume of gas = 2.5 L

Temperature of gas = 50°C (50+273 = 323 k)

Pressure of gas = 650 mmHg (650/760 =0.86 atm)

Molecules of N₂= ?

Solution:

PV= nRT

n = PV/RT

n = 0.86 atm × 2.5 L /0.0821 atm. mol⁻¹. k⁻¹. L × 323 k

n = 2.15 atm. L /26.52 atm. mol⁻¹.L

n = 0.08 mol

Number of moles of N₂ are 0.08 mol.

Number of molecules:

one mole = 6.022 ×10²³ molecules

0.08×6.022 ×10²³ = 0.482 ×10²³ molecules

5 0

3 years ago

Think about water and how it rolls up on the beach. Think of all its qualities. Is it alive according to the characteristics of

gulaghasi [49]

Water is not alive because it has no living organisms.

6 0

3 years ago

In a balanced chemical reaction, the number of atoms of each element in the product(s) always equals the

dangina [55]

A ? Or c I thinkkkkkk

6 0

3 years ago

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Heyy guys, so basically i need help with stoichiometric calculation I will give you 100 points just to answer all of these answe

jeka94

Answer:

3. The mass of ethanol required is approximately 0.522869 g

The mass of ethanoic acid required is approximately 0.68156 g

4. The mass of iron (III) oxide required is approximately 285.952.189.095 tonnes

5. The mass of silver nitrate required is approximately 14.53 grams

6. The mass of copper oxide that would be needed is approximately 31.86 grams

7. a. The mass of the precipitate, Zn(OH)₂ formed is approximately 49.712 grams

b. The mass of the precipitate, Al(OH)₃ formed is approximately 13 grams

c. The mass of the precipitate, Mg(OH)₂, formed is approximately 14.579925 grams

Explanation:

3. The 1 mole of ethanol and 1 mole of ethanoic acid combines to form 1 mole of ethyl ethanoate

The number of moles of ethyl ethanoate in 1 gram of ethyl ethanoate, n = 1 g/(88.11 g/mol) = 1/88.11 moles

∴ The number of moles of ethanol = 1/88.11 moles

The number of moles of ethanoic acid = 1/88.11 moles

The mass of ethanol = (46.07 g/mol) × 1/88.11 moles = 0.522869 g

The mass of ethanoic acid in the reaction = 60.052 g/mol × 1/88.11 moles ≈ 0.68156 g

4. 1 mole of iron(III) oxide reacts with 1 mole of CO₂ to produce 1 mole of iron

The number of moles in 100 tonnes of iron= 100000000/55.845 = 1790670.60614 moles

The mass of iron (III) oxide required = 159.69 × 1790670.60614 = 285952189.095 g ≈ 285.952.189.095 tonnes

5. The number of moles of NaCl in 5 grams of NaCl = 5 g/58.44 g/mol = 0.0855578371 moles

The mass of silver nitrate required, m = 169.87 g/mol × 0.0855578371 moles ≈ 14.53 grams

6. The number of moles of CuSO₄·5H₂O in 100 g of CuSO₄·5H₂O = 100 g/(249.69 g/mol) ≈ 0.4005 moles

The mass of copper oxide required, m = 79.545 g/mol × 0.4005 moles ≈ 31.86 grams

7. a. The number of moles of NaOH in the reaction = 20 g/(39.997 g/mol) ≈ 0.5 moles

2 moles of NaOH produces 1 mole of Zn(OH)₂

0.5 moles of NaOH will produce 0.5 mole of Zn(OH)₂

The mass of 0.5 mole of Zn(OH)₂ = 0.5 mole × 99.424 g/mol = 49.712 grams

The mass of the precipitate, Zn(OH)₂ formed = 49.712 grams

b. 6 moles of NaOH produces 2 moles Al(OH)₃

20 g, or 0.5 mole of NaOH will produce (1/6) mole of Al(OH)₃

The mass of the precipitate, Al(OH)₃ formed, m = 78 g/mol×(1/6) moles = 13 grams

c. 2 moles of NaOH produces 1 mole of Mg(OH)₂, therefore;

20 g or 0.5 moles of NaOH formed (1/4) mole of Mg(OH)₂

The mass of the precipitate, Mg(OH)₂, formed, m = 58.3197 g/mol × (1/4) moles = 14.579925 grams

3 0

3 years ago

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