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3 years ago

Calculate the empirical formula of a compound that is 42.9% Carbon and 57.1% Oxygen.

Chemistry

1 answer:

Marrrta [24]3 years ago

4 0

Answer:

CO.

Explanation:

Assuming the given percentages are by mass, we can solve this problem via imagining we have 100 g of the compound, if that were the case we would have:

42.9 g of C

57.1 g of O

Now we convert those masses into moles, using the elements' respective molar masses:

42.9 g of C ÷ 12 g/mol = 3.57 mol C

57.1 g of O ÷ 16 g/mol = 3.58 mol O

As the number of C moles and O moles is roughly the same, the empirical formula for the compound is CO.

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Technetium (Tc; Z = 43) is a synthetic element used as a radioactive tracer in medical studies. A Tc atom emits a beta particle

Sedaia [141]

Question in incomplete, complete question is:

Technetium (Tc; Z = 43) is a synthetic element used as a radioactive tracer in medical studies. A Tc atom emits a beta particle (electron) with a kinetic energy (Ek) of $4.71\times 10^{-15}J$ . What is the de Broglie wavelength of this electron (Ek = ½mv²)?

Answer:

$6.762\times 10^{-12} m$ is the de Broglie wavelength of this electron.

Explanation:

To calculate the wavelength of a particle, we use the equation given by De-Broglie's wavelength, which is:

$\lambda=\frac{h}{\sqrt{2mE_k}}$

where,

= De-Broglie's wavelength = ?

h = Planck's constant = $6.624\times 10^{-34}Js$

m = mass of beta particle = $9.1094\times 10^{-31} kg$

$E_k$ = kinetic energy of the particle = $4.71\times 10^{-15}J$

Putting values in above equation, we get:

$\lambda =\frac{6.624\times 10^{-34}Js}{\sqrt{2\times 9.1094\times 10^{-31} kg\times 4.71\times 10^{-15}J}}$

$\lambda = 6.762\times 10^{-12} m$

$6.762\times 10^{-12} m$ is the de Broglie wavelength of this electron.

3 0

3 years ago

Calculate the molar solubility of copper(II) arsenate (Cu3(AsO4)2) in water. Use 7.6 x 10^-36 as the solubility product constant

Molodets [167]

Molar solubility is the number of moles of a substance (the solute) that can be dissolved per liter of solution before the solution becomes saturated. We calculate as follows:

3Cu2+ + 2(AsO4)3- = Cu3(AsO4)2

7.6 x 10^-36 = (3x^3)(2x^2)
x = 6.62 x 10^-8 M

8 0

3 years ago

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Read the selection from the section "Molecules In Motion." The molecules in the hot soup are traveling faster overall than they

Hoochie [10]

Answer: The author used the word "conversely" because the first statement he made is in CONTRAST to the second statement he made.

Explanation:

Matter is made up of atoms or molecules that are in constant motion. The motion of these tiny particles ( molecules) gives the object energy. The movement of these molecules depends on the state of matter which includes

--> GASEOUS STATE: Here, the particles are completely free to move and are always in motion.

--> LIQUID STATE: particles in this state slide by one another and are always in motion.

--> SOLID STATE: particles in this state are held tightly together but are always in motion.

Also, the molecules in motion are greatly affected by temperature changes. Increase in temperature will cause the particles in the liquid to move faster. Such is seen when soup is heated, the molecules travel faster than before. But the OPPOSITE is seen in an ice cube. This is because the ice cube is in solid state and of a lower temperature.

7 0

3 years ago

Lead forms two compounds with oxygen. One contains 2.98g of lead and 0.461g of oxygen. The other contains 9.89g of lead and 0.76

aliina [53]

The given question is incomplete, the complete question is:

Lead forms two compounds with oxygen. One contains 2.98g of lead and 0.461g of oxygen. The other contains 9.89g of lead and 0.763g of oxygen. For a given mass of oxygen, what is the lowest whole-number mass ratio of lead in the two compounds that combines with a given mass of oxygen?

Answer:

The lowest whole-number mass ratio in the two compounds is 1:2.

Explanation:

There is a need to find the mole ratio between lead and oxygen atoms in order to find the whole-number mass ratio of lead in the two compounds. In the first compound, the given mass of lead is 2.98 grams, the molar mass of lead is 207.2 gram per mole.

The no. of moles can be determined by using the formula,

moles = mass/molecular mass

moles = 2.98 g/207.2 g/mol

= 0.0144 moles

The mass of oxygen in the compound I is 0.461 grams, the molecular mass of oxygen is 16 gram per mol.

moles = 0.461 g /16 g/mol

= 0.0288 moles

The ratio between the lead and oxygen in the compound I is 0.0144/0.0288 = 1:2

On the other hand, in the compound II, the mass of lead given is 9.89 grams, therefore, the moles of lead in compound II is,

moles = 9.89 g / 207.2 g/mol

= 0.0477 moles

The mass of oxygen given in compound II is 0.763 grams, the moles of oxygen present in the compound II is,

moles = 0.763 g / 16 g

= 0.0477 moles

The ratio between the lead and oxygen in the compound II is, 0.0477 moles lead /0.0477 moles oxygen = 1:1

Hence, of the two compounds, the lowest ratio is found in the compound I, that is, 1:2.

4 0

3 years ago

If the frequency of a wave is 68 hertz then the period of the wave is going to be

tigry1 [53]

The answer is 4.41x10^1 m.

Explanation:

You would use this formula to calculate it
λ = C/f

Where,

λ (Lambda) = Wavelength in meters

c = Speed of Light (299,792,458 m/s)

f = Frequency

So we have the frequency, 68 Hz, and we have the speed of light. Now we put it into the equation and it will look like this:

λ= (299,792,458 m/s) / (68 Hz)

λ= 4.41x10^1

6 0

3 years ago

Read 2 more answers