Chemistry Chapter One & Two

How many moles are in 10.0 grams of Magnesium (Mg)?

0.411g/Mg

Write 0.000001357 in scientific notation.

1.357 X 10^-6

Put 15.9171 into scientific notation.

1.59171 x 10^1

How many cm are in 1.91 yards?

1.91YD(1M/1.094 YD) (100CM/1M) = 175CM

Record the temperature on the thermometer to the correct number of significant digits.

103.4

Convert 41oC into both oF and K.

105.8

Calculate the correct number of significant figures for the following mathematical operation: 108.5+0.92

109.4

: How many protons, neutrons and electrons are in the carbon-14 isotope?

6 protons, 8 neutrons, 6 electrons.

How many significant figures does 1135.61 have?

6 significant figures. All non-zero so all count as significant.

Write out 6.02 x 10^23 in non-scientific notation.

602,000,000,000,000,000,000,000

The reported volume for the water in the cylinder to the is right 73.36. Is this the correct number of significant digits?

73.4

Find the protons, neutrons and electrons in each of the following elements:

12C6 6 protons, 6 neutrons, 6 electrons 13C6 6, 7, 6 12Mg24 12, 12, 12 82Pb207 82, 125, 82 80Hg201 80, 121, 80 92U234 92, 142, 92 92U23592, 143, 92

Liquid helium has a temperature of 4K. What is this temperature in degrees Celsius?

oC =K -273 = 4 - 273 = -269 oC

The scientific method is based in observation and experimentation.

true

True or False. In liquids, atoms are free to move relative to one another but are still attracted to one another.

true

True or False. Molecules (also called compounds) can be described as two or more different types of atoms chemically joined together

true

A dog weighs approximately 15.5 pounds. If there are 2.205 lb in 1 kg (1 kg = 2.205 lb), how many kg does the dog weigh?

weight(kg) = 15.5lb (1kg/2.205 lb) = 7.03kg

An airplane has 150,231 L of jet fuel. If the density of the fuel is 0.768 g/cm3, what is the mass of the jet fuel?

(150,231 L)(((1 mL))/(1x10-3 L))(((1cm3))/(1 mL))((0.768g)/1cm3)=1.15377 x 108 g ANSWER: 1.15377 X 10^8

A person travels from Europe to New York City and has 53.91 Euros (€). How much in US dollars ($) does the person have?

1 euro= 1.11 usd; $59.84

Calculate the correct number of significant figures for the following mathematical operation: 108.5 * 0.92

1.0*10^1

How many protons are in each chlorine atom?

17

What is the molecular weight of water?

18.015g/mol

Write 20,000,000,000,000,000,000,000 in scientific notation.

2 X 10^22

Round 1.9756 to 2-significant figures.

2.0

The mass of a proton is 1.67 × 10-27 kg. What is the mass of a proton in picograms (pg)? 1 kilogram (kg) = 1,000 grams (g); 1 x 10-12 grams = 1 picograms (pg).

2.13 X 10^16 pg

How tall in the units of yards is a person who is 2m in height?

2.2YD

Calculate the correct number of significant figures for the following mathematical operation: 15.9171)(32.62)/(101.92 - 99.567)(88.561)

2.5 or 3 sig figs

The density of a metal cylinder is 7.5 g/cm3, and its volume is 2.8436 cm3. Calculate its mass.

21g

What is the atomic symbol for 26 Protons and 30 neutrons?

26Fe56

In the movie The Enemy Below (1957), to escape an American destroyer a German submarine (or U-boat) attempts to rest on the bottom of the ocean at 170 fathoms. Convert fathoms to both meters and feet.

311m

In The Lord of the Rings, Frodo and Sam rappel down a cliff using a rope 30 ells long. How long was the rope in both feet and meters?

34m

Determine the volume of an object that has a mass of 417.6 g and a density of 11.3 g/mL.

37.0mL

Calculate the correct number of significant figures for the following mathematical operation: 53.1956 * 99.127721

5.27316 * 10^4

A brick of platinum has a density of 21.4 g/mL and has a mass of 1,150 grams. What is the volume (in mL) of the platinum brick?

53.7mL

: A gold necklace has a measured density of 11.51 g/mL and occupies a volume of 7.59 mL, what is the mass (in g) of the necklace?

87.4g

The average annual per person crude oil consumption in the United States is 15,615 dm3. What is this value in cubic inches?

9,5289 * 105IN^3

What is the correct scientific notation for the number 0.000000000913?

9.13 x 10^-10.

What are the differences between a scientific hypothesis, a theory, and a law?

A hypothesis is a tentative example of some regularity in nature. A theory is a texted explanation of a basic natural phenomena. A law is a concise statement or equation about a fundamental relationship or regularity in nature.

Using careful experimentation Antoine Lavoisier (among others) showed that matter can neither be created nor destroyed in normal chemical reactions, but can be rearranged. Using modern scientific terminology, what would we call the statement "matter can neither be created nor destroyed in normal chemical reactions, but can be rearranged"? a)an Observation b)an Experiment c)a Hypothesis d)a Theory a Law

A...Law. It is the law of conservation of matter

Which of the statements below are part of the scientific method? a)observation and measurement b)formation of a hypothesis c)refinement of a hypothesis as needed d)testing of a hypothesis by experimentation

All of the above steps are part of the scientific method.

A substance that can't be chemically broken down into simpler substances by chemical means is considered to be an element, a compound or a mixture?

An element (yes, elements are made up of subatomic particles but we ignore these when looking at element, compound or mixture).

The diagram below represents the combustion (or burning) of gasoline (C8H18) in the presence of oxygen (O2) to for carbon dioxide and water. Based on the diagram is this a physical or chemical change?

Chemical Change

Based on the molecular diagram, classify the change as chemical or physical (the spheres represent atoms, different shading indicates different types of atoms)

Chemical Change; the reactants and products are not the same

Is the reaction below a physical or chemical change? c4h10(i)+o2(g) -> CO2(G)+H2O(G)

Chemical Change; the reactants and products are not the same

What is the difference between Co and CO?

Co is element number 27, cobalt ( the small o after the C indicates we are dealing with an element). CO is the chemical molecule or compound carbon monoxide.

Define element, compound and mixture. Give an example of each one.

Element: Composed of 1-type of atom (e.g., Helium (He), hydrogen (H2)). Compound: Composed of 2-or more types of different atoms types of atoms combined in fixed proportions (e.g., H2O, CO2) Mixture. Has a variable composition. A material system made of 2-or more different substances (atoms, compounds, etc.) which are mixed but not chemically combined. For example, air is composed of elemental nitrogen (N2) and oxygen (O2) that are not chemically combined, or bonded together (they exist independently of one another)

True or False. There are five carbon atoms in C6H5OH.

FALSE; There are 6 carbon atoms in the molecule.

True or False. Energy is created when gasoline burns.

False We do not create energy...ever! We simply take the energy that is stored in chemical molecules and release it. Yeah, I know, I'm belaboring the point. There might be a good reason for that...

True or false. Temperature is the same as heat

False, they are not the same thing. Look back at the notes to convince yourself of this. Also, knowing what each one is (or the definition) are fair exam questions.

True or False. Matter is destroyed in chemical reactions.

False. The first law states that matter is neither created Nor destroyed, only rearranged. Again, matter is NOT destroyed in chemical reactions.

True or False. When humans burn wood, they are creating energy.

False. We do not create energy...ever! We simply take the energy that is stored in chemical molecules and release it. We do not create energy...ever!

True or False. Molecules (also called compounds) can be described as Mixtures of two or more elements that have a specific ratio between components

False. Compounds are composed of 2 or more different types of elements (such as H2O) chemically attached Together. This definition says nothing about them being attached Together, they could simply be mixed together as separate Elements.

True or False. Molecules (also called compounds) can be described as Substances that cannot be broken down into simpler substances.

False. Compounds are composed of 2 or more different types of elements (such as H2O) joined together. They can be broken down into their elemental forms.

There are two carbon atoms in carbon dioxide (CO2).

False. There is 1-carbon atom and 2-oxygen atoms.

Which state of matter has an indefinite volume and indefinite shape? Gas, liquid, solid.

Gas

What does the term atomos mean?

Indivisible - cannot be broken up into smaller pieces

What theory did John Dalton formulate? Which of his original postulates do we now know is/are incorrect?

John Dolton formulated modern atomic theory: an explanation of the structure of matter in terms of different combinations of very small particles. Postulate 1 is now known to be incorrect : atoms are NOT indivisible and indestructible (they are composed) of even smaller particle that can be removed from the atom. Postulate 2 is also known to be incorrect: an element is not composed of only type of atom. Isotopes exist ,atoms with the same atomic number (hence the same atom), but different mass numbers.

A beaker of liquid has a temperature of 152K. What is the temperature in oC?

K= oC + 273.15 oC= K -273.15= 152-273.25 = -121oC

Which state of matter has an definite volume and indefinite shape? Gas, liquid, solid.

Liquid

The chemicals shown below both contain hydrogen and oxygen atoms. Are they the same compound?

NO. Water contains one oxygen and two hydrogen atoms, and is safe for humans to consume (it's necessary for life). Hydrogen peroxide contains two oxygen atoms and two hydrogen atoms, and is not safe to consume (it can damage tissue lining and cells).

What does the formula NaCN tell us about this compound?

NaCN is a chemical molecule (or compound) composed of three elements bonded, or chemically attached, together : Na is sodium (element 11) C is carbon (element 6) N is nitrogen (element 7) For each sodium there is one carbon and one nitrogen

Does the following chemical reaction obey the law of conservation of matter (the amount of reactants and products is listed below the equation; the species in parentheses are the elements or compounds represented by the names):

No, it does not. The mass on the left is different from the mass on the right.

Pure Rhodium has a density (at 25oC) of 12.41 g/mL (or g/cm3). If a rhodium necklace weighs 2.49g and has a volume of 0.519 mL (or 0.519 cm3), is the necklace composed of pure rhodium?

No, it is not pure rhodium. To be pure rhodium the answer must be approximately 12.41 g/mL. We solved and got 4.80 g/mL.

Carbon monoxide has the chemical formula CO while carbon dioxide has the chemical formula CO2. They are both composed of carbon and oxygen atoms in different ratios. Will they have identical chemical and physical properties?

No, they will not. The formulas are different (CO has one C and one O whereas CO2 has one C and two O's) so the properties will be different.

The reported volume for the water in the cylinder to the is right 73.36. Is this the correct number of significant digits?

Nope. It should be 73.4 The 73 is known accurately, the '4' has to be estimated.

Which elementary particle(s) is (are) in the nucleus?

PROTONS AND NEUTRONS

Based on the diagram is this a physical or chemical change? The molecule in question is H2O.

Physical Change

Is the reaction below a physical or chemical change? C4H10(I)-> C4H10(G)

Physical Change; the reactants and products are identical (are the same), only the state of matter has changed from liquid to gas.

Where are the subatomic particles located in atoms?

Protons and neutrons are inside the nucleus, electrons are surrounding the nucleus.

List the properties (charges, masses) of protons, neutrons and electrons.

SEE SLIDE 231 OF CHAPTER 2

Explain step by step Rutherford's gold foil experiment and the conclusions drawn from it.

SEE SLIDES 223-230 OF CHAPTER 2

Which state of matter has a definite volume and definite shape? Gas, liquid, solid.

Solid

True or False. There are 10.81 grams of Boron in 1 mole of Boron.

TRUE

What is the difference between 8S and S8?

The 8 in front of the capital S (for sulfur) indicates that we have 8 atoms of sulfur that are not attached together. This is sometimes called a prefix. The 8 as a subscript of the capital S (for sulfur), S, means that there are 8 sulfur atoms attached together. t is still an element since they are all sulfur atoms, but they ae attached together in the element form.

How did the law of conservation of matter lead to Dalton's original atomic theory?

The law of conservation of matter showed that matter reacts in consistent predictable ways. That matter is not destroyed in chemical reactions, simply rearranged. Also, that the concept of different atoms with different properties leading to different materials might be a valid explanation for matter in the universe.

Define the law of conservation of mass (or matter). Give a chemical example of the law of conservation of matter.

The law of conservation of matter states that in a chemical reaction, matter is neither created nor destroyed. An example form the text is pasted below, pay particular attention to the masses of products (on the left) and reactants (on the right).

What subatomic particle(s) does the atomic number refer to?

The protons

Is the process represented below a physical or a chemical change? Assume the chemical in the picture is water.

This is a physical change, we are changing the phase of matter but not changing the chemical formula.

The picture on the left is of carbon dioxide in the solid form (CO2(s)) at temperatures lower than -78.5 oC. When the temperature gets above -78.5 oC the carbon dioxide changes phase to gaseous CO2, CO2(g) (figure on the right). Convert -78.5oC to Kelvin and determine whether going from the solid to the gas phase is a chemical or a physical change.

This is a physical change, we are changing the phase of matter, but no changing the chemical formula

Antoine Lavoisier used experimentation to determine that matter is neither created nor destroyed in normal chemical reactions? Using modern scientific terminology is this a hypothesis, theory or law?

This is the law of conservation of matter. A concise statement about a fundamental relationship or regularity in nature.

True or False. The mass of the reactants has to equal the mass of the products in a chemical reaction.

True

True or False. Modern experimental evidence indicates that atoms can be broken up into smaller particles.

True There is overwhelming evidence that atoms can be broken up into smaller, subatomic, particles.

The law of conservation of matter is based on experimental evidence. True or false?

True, Laws are based on experimental evidence.

Atomic theory is based on experimental evidence. True or false?

True, theories are based on experimental evidence.

True or False. 235U and 238U have the same number of Protons.

True. They each have 92 protons.

The density of a metal cylinder is 4.5 g/cm3 and its mass is 19.81357 g. Calculate its volume. Report your answer to the correct number of significant figures.

V= M/D = (19.81357G / 4.5 G/CM^3)= 4.4 CM^3

Leucippus and Democritus propose that there must be tiny, indivisible particles using no experimental evidence. Is this a hypothesis, theory or law?

Was experimental evidence used to develop this model? The answer is no, therefore it is an hypothesis.

In the Figure below, liquid water is being vaporized to steam (going from liquid water to gaseous water). Which diagram best represents the water molecules in steam?

Water has the formula H2O. In the figure, the oxygens are in red, and the hydrogens are white. It will be H2O as a liquid and as steam. In figure (a) the molecules are still H2O, in (b) the oxygens and hydrogens are no longer attached to each other (we now have O2 and 2H2), in (c) the atoms have completely broken apart, we have 2O and 4H. Making (a) the correct answer.

Each of the following is a definition for a scientific principle. Please give the name of the scientific principle that goes with each definition

a)Elements can combine in more than one set of proportions, with each set corresponding to a different compound. Law of Multiple Proportions b)Matter is neither created nor destroyed in chemical reactions, simply rearranged. Law of conservation of matter c)All matter is composed of indivisible and indestructible atoms. (part of Dalton's original atomic theory, this postulate is now known to be incorrect) d)All samples of a given compound have the same proportions of their constituent elements (Law of Definite Proportions)

Determine whether each change is chemical or physical.

a. Ice melting at ~0oC to form liquid water (this is a physical change. The water is not changing composition...it is still H2O in both phases). b. Gasoline burning in the presence of oxygen to form carbon dioxide, water and heat. (this is a chemical change. The gasoline is reacting with oxygen (i.e., burning) and being changed to carbon dioxide and water) c. Gasoline evaporating (going from liquid gasoline to gasoline in the gas phase) when it hits hot pavement. (this is a physical change. The gasoline is not changing composition...it has only changed phase, the atoms haven't been rearranged).

Which of the following statements about energy is FALSE? a) Energy can be converted from one type to another (for example, from kinetic to potential) b) Energy can neither be created nor destroyed, only rearranged. c) Kinetic energy is the energy associated with its position or composition. d) Energy is the capacity to do work.

c) Kinetic energy is due to motion, potential energy is due to position.

Which of John Dalton's original postulates for atomic theory are now known to be false? a)A chemical reaction is where a substance (or substances) are changed into one or more new substances. b)A compound or molecule is a type of matter composed of atoms of two or more elements chemically combined in fixed proportions. c)An element is a type of matter composed of only one kind of atom where all atoms of that element have identical properties (for example, each atom of uranium has the exact same properties). None of the above, all are true.

c)An element is a type of matter composed of only one kind of atom where all atoms of that element have identical properties (for example, each atom of uranium has the exact same properties). None of the above, all are true.

The Empire State building is 485 yards tall. How high is the Empire State building in meters? 1 yard = 0.914 meters

height(m)= 485 yards (0.914m / 1yard) = 443m

Sulfur (16S32) is found in nature as S8, eight atoms of sulfur attached together in a ring. Is sulfur an element or a compound?

it is an element (or S8 is one elemental form of sulfur)

Are the following physical or chemical changes? Continued from previous page.

〖"Fe" 〗_"2" "O" _"3(s)" "→Fe" ("s" )"+" "O" _"2(g)" This is a chemical change. The chemical formulas are changing... Iron oxide (or rust) is being converted to iron metal and oxygen gas (completely different species with completely different properties.