Q: Which equation describes the energy change ($$\Delta E) $$for an electron transition in the hydrogen atom according to Bohr’s model?

$$\Delta E = -2.18 \times 10$$^{-18}$$ \left( \frac{1}{n_f^2$} - \frac{1}{n_i^2$} \right) \, \text{J}$$

Q: Which of the following is the correct relationship for the energy of a photon?

$$E = h \nu = \frac{hc}{\lambda}$$

Q: Which of the following is a correct multi-step conversion for finding the number of atoms in 10.0 g of aluminum? (Molar mass of Al = 27.0 g/mol)

$$10.0 \, \text{g} \times \frac{1 \, \text{mol}}{27.0 \, \text{g}} \times \frac{6.02 \times 10$$^{23}$$ \, \text{atoms}}{1 \, \text{mol}}$$

Question 1

Which equation describes the energy change ($$\Delta E) $$for an electron transition in the hydrogen atom according to Bohr’s model?

Accepted Answer

$$\Delta E = -2.18 	imes 10$$^{-18}$$ \left( \frac{1}{n_f^2$} - \frac{1}{n_i^2$} ight) \, 	ext{J}$$

Question 2

A sample contains 0.50 mol of sodium atoms. How many sodium atoms are present in the sample?

Accepted Answer

$$3.01 	imes 10$$^{23}$$

Question 3

Which law states that a chemical compound always contains exactly the same proportion of elements by mass?

Accepted Answer

Law of Definite Proportions

Question 4

What is the wavelength (in meters) of an electron moving at $$2.0 	imes 10^6$ m/s? (Use m = 9.11$$ 	imes $$10^{-31} kg$$, $$h = 6.63 	imes 10$$^{-34}$$ J·s)

Accepted Answer

$$3.64 	imes 10$$^{-10}$$

Question 5

A naturally occurring element has two isotopes: 70% with mass 10.0 amu and 30% with mass 11.0 amu. What is the average atomic mass?

Accepted Answer

10.3 amu

Question 6

Which quantum number determines the shape of an atomic orbital?

Accepted Answer

Azimuthal quantum number ($$l)$$

Question 7

If $$n = 3$$, what are the possible values for the azimuthal quantum number $$l$$?

Accepted Answer

$$0, 1, 2$$

Question 8

A photon has a wavelength of $$4.00 	imes 10$$^{-7}$$ m. What is its energy? (h = 6.63$$ 	imes $$10^{-34} J$$·s, $$c = 3.00 	imes 10^8$ m/s)

Accepted Answer

$$4.97 	imes 10$$^{-19}$$ J

Question 9

Which of the following best describes the Heisenberg uncertainty principle?

Accepted Answer

$$\Delta x \cdot m \Delta v \geq \frac{h}{4 \pi}$$

Question 10

A sample of water is decomposed into hydrogen and oxygen. The total mass of the products equals the mass of the original sample. Which law does this illustrate?

Accepted Answer

Law of Conservation of Mass

Question 11

Which of the following is the correct relationship for the energy of a photon?

Accepted Answer

$$E = h 
u = \frac{hc}{\lambda}$$

Question 12

If the binding energy of an electron is $$2.0 	imes 10$$^{-19}$$ J and the energy of the incident photon is 3.0$$ 	imes $$10^{-19} J$$, what is the kinetic energy of the ejected electron?

Accepted Answer

$$1.0 	imes 10$$^{-19}$$ J

Question 13

Which of the following is NOT a criterion that defines a wave?

Accepted Answer

Density

Question 14

How many significant figures should be reported for the result of $$2.34 	imes 1.2$$?

Accepted Answer

2

Question 15

Which quantum number provides information about the orientation of an orbital in space?

Accepted Answer

Magnetic quantum number ($$m_l)$$

Question 16

A compound contains 12 g of carbon and 32 g of oxygen. What is the mass ratio of oxygen to carbon?

Accepted Answer

2.67

Question 17

Which of the following is a correct multi-step conversion for finding the number of atoms in 10.0 g of aluminum? (Molar mass of Al = 27.0 g/mol)

Accepted Answer

$$10.0 \, 	ext{g} 	imes \frac{1 \, 	ext{mol}}{27.0 \, 	ext{g}} 	imes \frac{6.02 	imes 10$$^{23}$$ \, 	ext{atoms}}{1 \, 	ext{mol}}$$

Question 18

If $$l = 2$$, what are the possible values for $$m_l$$?

Accepted Answer

$$-2, -1, 0, 1, 2$$

Question 19

Which of the following best describes the law of multiple proportions?

Accepted Answer

When two elements form more than one compound, the masses of one element that combine with a fixed mass of the other are in ratios of small whole numbers.

General Chemistry Exam 1 Study Guide: Chapters E, 1, and 2

Guida di studio - Domande di pratica

Study guide - Flashcard