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3 years ago

"what is the concentration of positive charge and mass in rutherford's atomic model called?"

1 answer:

3 0

The concentration of positive charge and mass in Rutherford's atomic model is called the nucleus. Rutherford's experiments involving the use of alpha particle beams directed onto thin metal foils demonstrated the existence of the nucleus. The nucleus of an atom contains positively charge particles called protons and other uncharged particles called neutrons. According to this model most volume of an atom is made up of an empty space.

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MAVERICK [17]

Answer:

Explanation:

7 0

3 years ago

The work function of palladium (Pd) is 5.22 eV. What is the minimum frequency of light to observe the photoelectric effect from

Ivan

Answer:

1)4×10^13Hz

2) 9.95×10-9J

Explanation:

From the image attached, it is clear that the work function of the palladium metal must first be obtained in joules. Then, the frequency is obtained from E=hf.

The kinetic energy if the photoelectrons is obtained as the difference between the energy of the photon and the work function of the metal.

4 0

3 years ago

Aspirin (C9H8O4) is synthesized by reacting salicylic acid (C7H6O3) with acetic anhydride (C4H6O3). The balanced equation isC7H6

prisoha [69]

<u>Answer:</u>

<u>For a:</u> The mass of acetic anhydride needed is 73.91 grams.

<u>For b:</u> The theoretical yield of aspirin is 130.43 grams.

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

<u>For a:</u>

Given mass of salicylic acid = $1.00\times 10^2g=100g$

Molar mass of salicylic acid = 138.121 g/mol

Putting values in equation 1, we get:

$\text{Moles of salicylic acid}=\frac{100g}{138.121g/mol}=0.724mol$

For the given chemical reaction:

$C_7H_6O_3+C_4H_6O_3\rightarrow C_9H_8O_4+CH_3COOH$

By stoichiometry of the reaction:

1 mole of salicylic acid reacts with 1 mole of acetic anhydride.

So, 0.724 moles of salicylic acid will react with = $\frac{1}{1}\times 0.724=0.724mol$ of acetic anhydride.

Now, to calculate the mass of acetic anhydride, we use equation 1:

Moles of acetic anhydride = 0.724 moles

Molar mass of acetic anhydride = 102.09 g/mol

Putting values in equation 1, we get:

$0.724mol=\frac{\text{Mass of acetic anhydride}}{102.09g/mol}\\\\\text{Mass of acetic anhydride}=73.91g$

Hence, the mass of acetic anhydride needed is 73.91 grams.

<u>For b:</u>

By stoichiometry of the reaction:

1 mole of salicylic acid is producing 1 mole of aspirin.

So, 0.724 moles of salicylic acid will produce = $\frac{1}{1}\times 0.724=0.724mol$ of aspirin.

Now, to calculate the mass of aspirin, we use equation 1:

Moles of aspirin = 0.724 moles

Molar mass of aspirin = 180.158 g/mol

Putting values in equation 1, we get:

$0.724mol=\frac{\text{Mass of aspirin}}{180.158g/mol}\\\\\text{Mass of aspirin}=130.43g$

Hence, the theoretical yield of aspirin is 130.43 grams.

4 0

3 years ago

How many moles are there in 3.612 x 1024 formula units of Na2SO4?

vitfil [10]

Answer:

<h3>Theanswer is 6 moles</h3>

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

$n = \frac{N}{L} \\$

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

$n = \frac{3.612 \times {10}^{24} }{6.02 \times {10}^{23} } \\$

We have the final answer as

<h3>6 moles</h3>

Hope this helps you

5 0

3 years ago

Density is d= m/vol. If a material has a mass of 65.5 g and a volume of 32.5 ml, it has a density of

ryzh [129]

Using the given formula, the density of the material is 2.015 g/mL

<h3>Calculating Density </h3>

From the question, we are to determine the density of the material

From the given formula

Density = Mass / Volume

And from the given information,

Mass = 65.5 g

and volume = 32.5 mL

Putting the parameters into the equation,

Density = 65.5/32.5

Density = 2.015 g/mL

Hence, the density of the material is 2.015 g/mL.

Learn more on Calculating density here: brainly.com/question/24772401

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8 0

2 years ago