Chemistry 113 exam I

Which of the following are chemical processes? 1. rusting of a nail 2. freezing of water 3. decomposition of water into hydrogen and oxygen gases 4. compression of oxygen gas

1 and 3

Osmium has a density of 22.6 g/cm3. What volume (in cm3) would be occupied by a 21.8 g sample of osmium? A) 0.965 B) 1.04 C) 493 D) 2.03 × 10-3 E) 2.03 × 103

A. .965 Work: 21.8g x 1cm/22.6g = 0.965 cm^3

In which one of the following numbers are all of the zeros significant? A) 100.090090 B) 0.143290 C) 0.05843 D) 0.1000 E) 00.0030020

A. 100.090090

What is the Law of Constant Composition?

All samples of a given compound have the same proportions of their constituent elements.

Consider the following selected postulates of Dalton's atomic theory: (i) Each element is composed of extremely small particles called atoms. (ii) Atoms are indivisible. (iii) Atoms of a given element are identical. (iv) Atoms of different elements are different and have different properties. Which of the postulates is(are) no longer considered valid? A) (i) and (ii) B) (ii) only C) (ii) and (iii) D) (iii) only E) (iii) and (iv)

B. (ii) only

The charge on the copper ion in the salt CuO is ________. A) +1 B) +2 C) +4 D) +3 E) +5

B. +2 Note: We must use the other element, which is Oxygen, to determine which charge the Copper ion has. Oxygen has a charge of negative two, so for the ionic compound to be balanced, Copper must have a charge of two as well.

Which of the following has the same number of significant figures as the number 1.00310? A) 1 × 10^6 B) 199.791 C) 8.66 D) 5.119 E) 100

B. 199.791

__________ typically form ions with a 2+ charge. A) Transition metals B) Alkaline earth metals C) Alkali metals D) Chalcogens E) Halogens

B. Alksline earth metals

Expressing a number in scientific notation ________. A) changes its value B) removes ambiguity as to the significant figures C) removes significant zeros D) allows to increase the number's precision E) all of the above

B. Removes ambiguity as to the significant figures

Of the following, only ________ is an extensive property. A) density B) volume C) boiling point D) freezing point E) temperature

B. Volume

Which of the following is an illustration of the law of constant composition? A) Water boils at 100 °C at 1 atm pressure. B) Water is 11% hydrogen and 89% oxygen by mass. C) Water can be separated into other substances by a chemical process. D) Water and salt have different boiling points. E) Water is a compound.

B. Water is 11% Hydrogen and 89% Oxygen by mass.

The number with the most significant zeros is ________. A) 0.00002510 B) 0.02500001 C) 250000001 D) 2.501 × 10-7 E) 2.5100000

C. 2510000001

For which of the following can the composition vary? A) pure substance B) element C) both homogeneous and heterogeneous mixtures D) homogeneous mixture E) heterogeneous mixture

C. Both Heterogeneous and Homogeneous Mixture

A separation process that depends on differing abilities of substances to form gases is called ________. A) filtration B) solvation C) distillation D) chromatography E) All of the above are correct.

C. Distillation

Which one of the following has the element name and symbol correctly matched? A) S, sodium B) Tn, tin C) Fe, iron D) N, neon E) B, bromine

C. Fe, Iron

What is the Celsius Formula?

C= 5/9 (F-32)

Which atom has the largest number of neutrons? A) phosphorus-30 B) chlorine-37 C) potassium-39 D) argon-40 E) calcium-40

Calculate the number of neutrons by subtracting the atomic number from the atomic mass of the isotope: 30 P = 15 protons + 15 neutrons 37 Cl = 17 protons + 20 neutrons 39 K = 19 protons + 20 neutrons 40 Ar = 18 protons + 22 neutrons 40 Ca = 20 protons + 20 neutrons

Round the number 3456.5 to two significant figures. A) 3400.0 B) 3400 C) 3000 D) 3500 E) 3000.0

D. 3500

Accuracy refers to ________. A) how close a measured number is to zero B) how close a measured number is to the calculated value C) how close a measured number is to other measured numbers D) how close a measured number is to the true value E) how close a measured number is to infinity

D. How close a measurement number is to the true value.

Which one of the following is not an intensive property? A) density B) temperature C) melting point D) mass E) boiling point

D. Mass

Acceleration due to gravity of a free-falling object is 9.8 m/s2. Express this in millimeters/millisecond2. A) 9.8 × 10^-9 B) 9.8 × 10^3 C) 9.8 × 10^-6 D) 9.8 × 10^6 E) 9.8 × 10^-3

E. 9.8 x 10^-3

If matter is uniform throughout and cannot be separated into other substances by physical means, it is ________. A) a compound B) either an element or a compound C) a homogeneous mixture D) a heterogeneous mixture E) an element

E. Element

Which statement below correctly describes the responses of alpha, beta, and gamma radiation to an electric field? A) Both beta and gamma are deflected in the same direction, while alpha shows no response. B) Both alpha and gamma are deflected in the same direction, while beta shows no response. C) Both alpha and beta are deflected in the same direction, while gamma shows no response. D) Alpha and beta are deflected in opposite directions, while gamma shows no response. E) Only alpha is deflected, while beta and gamma show no response.

E. Only Alpha is deflected, while beta and gamma show no response.

Homogeneous mixtures are also known as ________. A) solids B) compounds C) elements D) substances E) solutions

E. Solution

What is the Fahrenheit Formula?

F= 9/5 (C)+32

A combination of sand, salt, and water is an example of a ________.

Heterogeneous Mixture

Which one of the following is often easily separated into its components by simple techniques such as filtering or decanting?

Heterogeneous Mixture

What is the Kelsus formula?

K= C+273.15

One angstrom, symbolized Å, is 10-10 m. 1 cm3 = ________ Å3. A) 10^24 B) 10^-24 C) 10^30 D) 10^-30 E) 10^-9

So one angstron is 10^-10 m, which means it is 10^-8 cm, which means there are 10^8 angstroms in 1 cm. **1 cm^3 = 1 cm * 1 cm * 1 cm 1 cm^3 = 10^8 * 10^8 * 10^8 angstrom^3 1 cm^3 = 10^24 angstrom^3

What is an extensive property?

a property that depends on the amount of matter in a sample ( mass, volume, energy)

What is an intensive property?

a property that depends on the type of matter in a sample, not the amount of matter. (bioling point, density, color, etc)

What is precision?

refers to the proximity of several measurements to each other/

What is Distillation?

uses difference in boiling points of substance to separate a homogenous mixture into its components

Which one of the following is the highest temperature? A) 38 °C B) 96 °F C) 302 K D) the freezing point of water

** Convert all temperatures into the same unit A. 302 - 273 = 30C B. 38C C. (96-32)(5/9) = 36C D. Obviously one has to be the highest. E. 0C