CHEM 107 - exam 1 - module 1-3

Select all that correctly describe a chemical formula. -A chemical formula that does not contain subscript numbers consists of a one-to-one ratio of the elements that are present. -A chemical formula uses subscript numbers to show the relative proportions of the elements in the compound. -A subscript present in a chemical formula applies to all elements preceding it in the formula. -A chemical formula describes the composition of a compound using the symbols for the elements that make up the compound. -A mixture is represented with a chemical formula.

-A chemical formula that does not contain subscript numbers consists of a one-to-one ratio of the elements that are present. -A chemical formula uses subscript numbers to show the relative proportions of the elements in the compound. -A chemical formula describes the composition of a compound using the symbols for the elements that make up the compound.

Explain how a fuel such as gasoline has both kinetic and potential energy. -A fuel has potential energy because it is a reactive substance with stored energy that it releases when it burns with oxygen. -A fuel has kinetic energy because its molecules have motion. -A fuel has kinetic energy because it is a reactive substance with stored energy that it releases when it burns with oxygen. -A fuel has potential energy because its molecules have motion.

-A fuel has potential energy because it is a reactive substance with stored energy that it releases when it burns with oxygen. -A fuel has kinetic energy because its molecules have motion.

Select all that correctly describe a homogeneous mixture. -A homogeneous mixture is a type of pure substance. -A homogeneous mixture has a uniform composition throughout. -A homogeneous mixture is clear in appearance and would never have a color. -Any microscopically small portion of a homogeneous mixture would have the same composition as any other portion.

-A homogeneous mixture has a uniform composition throughout. -Any microscopically small portion of a homogeneous mixture would have the same composition as any other portion.

Select all the options that are examples of physical change(s). -A mixture is separated into its components. -A fuel is burned in air to form carbon dioxide and water. -Water evaporates slowly over time. -electricity is used to change water into hydrogen and oxygen gases. -A sample is heated and it melts.

-A mixture is separated into its components. -Water evaporates slowly over time. -A sample is heated and it melts.

Which of the following changes ALWAYS indicates that a chemical change has taken place? -The mass of the product(s) is less than the mass of the starting material(s). -Energy is given out by the process. -A new substance with different physical properties forms during the process. -The color of the substance is changed during the process.

-A new substance with different physical properties forms during the process.

Select all that represent qualitative observations. -A solid sample feels smooth to the touch. -A sample of water has a density of 0.99g/mL. -the color of a sample is red. -Liquid water takes on the shape of its container. -A metal is shiny in appearance.

-A solid sample feels smooth to the touch. -the color of a sample is red. -Liquid water takes on the shape of its container. -A metal is shiny in appearance.

Which of the following options correctly describe physical and chemical changes? -After a physical change, the chemical composition of the substance remains unchanged. -A physical change may involve a phase change. -A chemical change results in the formation of one or more new substances. -A chemical change need not involve a chemical reaction. -The physical properties of a substance remain unchanged during a chemical change.

-After a physical change, the chemical composition of the substance remains unchanged. -A physical change may involve a phase change. -A chemical change results in the formation of one or more new substances.

Select all the equations that represent chemical changes. -H2O(l) ---> H2O(s) -C(s) + O2(g) ---> CO2(g) -2H2(g) + O2(g) ---> 2H2O(g) -CO2(s) ---> CO2(g)

-C(s) + O2(g) ---> CO2(g) -2H2(g) + O2(g) ---> 2H2O(g)

Select all that correctly describe the features of the periodic table. -Each column in the periodic table is called a group or family of elements. -The elements in each row of the periodic table share similar properties. -The periodic table is used by chemists to classify mixtures. -The elements in each column of the periodic table share similar properties

-Each column in the periodic table is called a group or family of elements. -The elements in each column of the periodic table share similar properties

Which of the following options correctly describe the phases of matter? -The particles of a solid are more organized than those of a liquid or gas. -A liquid does not have a fixed volume because its particles are disorganized. -A liquid has large spaces between its particles. -A gas cannot be compressed readily. -The particles of a gas are far apart under normal conditions of temperature and pressure.

-The particles of a solid are more organized than those of a liquid or gas. -The particles of a gas are far apart under normal conditions of temperature and pressure.

How does the symbol for an element differ from the formula used to represent a compound? -The symbol for an element may contain more than one letter, but only one letter is uppercase, whereas the formula of a compound will contain more than one uppercase letter. -An element symbol only consists of one letter, whereas a compound formula will contain more than one letter. -The formula for a compound will always contain subscripts, whereas an element symbol will not.

-The symbol for an element may contain more than one letter, but only one letter is uppercase, whereas the formula of a compound will contain more than one uppercase letter.

Select all the options that correctly describe volume. -The volume of a sphere is equal to 4/3 x Pi x r. -The volume of a cube is equal to length multiplied by width multiplied be height. -Volume is a type of qualitative physical property. -Volume is a three-dimensional quantity. -Volume is the amount of space a substance occupies.

-The volume of a cube is equal to length multiplied by width multiplied be height. -Volume is a three-dimensional quantity. -Volume is the amount of space a substance occupies.

Which of the following options correctly describe scientific notation? -There will always be one digit before the decimal point in this type of notation. -There may be more than one digit before the decimal point in this type of notation. -A number smaller than 1 will have a negative exponent on the 10. -A negative exponent must be used to indicate that a number is larger than 1. -In scientific notations, zeros at the end of the numbe dare always omitted

-There will always be one digit before the decimal point in this type of notation. -A number smaller than 1 will have a negative exponent on the 10.

Which of the following are examples of homogeneous mixtures? -pure water containing no additional compounds -a well-mixed sample of sugar water -a jar of chunky salsa -a red sports drink containing sugar, salt, and food clothing

-a well-mixed sample of sugar water -a red sports drink containing sugar, salt, and food clothing

Which of the following are physical properties? -ability to burn in air -chemical stability -melting point -color -density

-melting point -color -density

1. A battery is used to make a toy car move. 2. Electricity runs through a stove and heats it up. 3. Electricity is used to change water into hydrogen and oxygen gases. 4. A person pedals quickly on a spinning bike to light up a computer screen on the bike. Match each above situation to the type of energy conversion it describes below. -Mechanical energy is changing to electrical energy. -Electrical energy is changing to heat energy. -Electrical energy is changing to chemical energy. -Chemical energy is changing to mechanical energy.

1. Chemical energy is changing to mechanical energy. 2. Electrical energy is changing to heat energy. 3. Electrical energy is changing to chemical energy. 4. Mechanical energy is changing to electrical energy.

Place the steps required to solve a linear equation involving fractions in the correct, starting with the first step at the top of the list. 1. Isolate the combined x term on the side of the equation by adding the appropriate number to both sides of the equation. 2. Multiply all terms by the common denominator. 3. Express all terms (including whole numbers) as fractions with the same denominator. 4. Divide both sides of the equation by the coefficient of x to obtain the value of x. 5. Combine like terms

1. Express all terms (including whole numbers) as fractions with the same denominator. 2. Multiply all terms by the common denominator. 3. Combine like terms 4. Isolate the combined x term on the side of the equation by adding the appropriate number to both sides of the equation. 5. Divide both sides of the equation by the coefficient of x to obtain the value of x.

Classify each of the below either as a chemical property or chemical property. 1. boiling point 2. ability to react with acid 3. viscosity 4. methane burns in air 5. ice melts at room temperature

1. physical property 2. chemical property 3. physical property 4. chemical property 5. physical property

Scientific notation expresses a quantity with a single nonzero digit before the decimal point and followed by the number ________ raised to the appropriate power.

10

Why are changes of state (i.e. melting) considered physical changes and not chemical changes?

A change of state does not involve a change in the chemical composition of a substance.

How is energy involved in phase changes, such as the melting of a solid to form a liquid?

Heat may be absorbed or released during a phase change.

A ____________ change involves no change in composition; the substance merely changes physical form.

Physical

______________ error is commonly present in measurements and can be minimized by repeated measurements and skill level of the person taking the measurements.

Random

Why can a logarithm only be taken for a unitless number?

The logarithm of a unit has no meaning, because there is no power to which a number can be raised to convert it into a unit.

A white solid is mixed with a clear liquid in a beaker. The mixture fizzes, it turns green, and the beaker feels hot to the touch. what kind of change is occurring, and why?

This is a chemical change because new substances are being formed that have new physical properties.

A ____________ property measured through a chemical reaction, which involves changing the composition of the substance.

chemical

A _____________ change involves a change in composition; one or more new substances are formed.

chemical

A _____________ symbol contains two or more uppercase letters.

compound

A ______________ contains two or more different types of atoms bonded together.

compound

A ________________ is a chemical reaction is required to separate the components.

compound

A(n) _______________ contains two or more different types of atoms bonded together, whereas a(n) ______________ contains only one type of atom.

compound, element

gas to liquid is known as ___________.

condensation

To express a fraction using an exponent, raise the ________________ of the fraction to the appropriate negative exponent.

denominator

A ____________ symbol contains only one uppercase letter.

element

A copper pipe is a ______________.

element

An _____________ contains only one type of atom.

element

An ______________ cannot be broken down into simpler form of matter either by chemical reaction or physical means.

element

The potential energy of the system increases in an ______________ process, and also ______________ heat.

endothermic, absorbs

The potential energy of the system decreases in an ______________ process, and also ______________ heat.

exothermic, releases

____________ has no fixed shape or volume; can be compressed.

gas

A slice of pizza is a ________________ mixture.

heterogeneous

Blood is a water-based liquid in which solids (blood cells and platelets) are suspended. Classify blood as an element, compound, homogeneous mixture, or heterogeneous mixture.

heterogeneous mixture

The contents of a balloon after blowing it up by month if a _____________ mixture.

homogeneous

Water in a fountain containing dissolved dye is a _____________ mixture.

homogeneous

If energy cannot be created, what is the source of the energy that is released when gasoline is burned? The energy released....

is directly related to the energy in the bonds of the substances that make up gasoline.

___________ has fixed volume but not shape.

liquid

Anything that has mass and volume is called ____________.

matter

In a _______________, components can be separated by physical methods.

mixture

Is the following a pure element, pure compound, or mixture? NaCl(aq)

mixture

A _____________ property can be measured without a change in composition or identity.

physical

Properties that can be measured without changing the composition or identity of a substance are ______________ properties, whereas_____________ properties require a substance to be converted into some other substance in order to be determined.

physical, chemical

Energy due to position is called ____________ energy, whereas energy due to movement is _____________ energy.

potential, kinetic

Two oppositely charged particles held apart from each attract each other and have ______________ energy, which is converted to _____________ energy when the particles are allowed to move together.

potential, kinetic

Is the following a pure element, pure compound, or mixture? NaNO3(s)

pure compound

A sample that has a fixed chemical composition is a ______________, whereas a sample containing different components that can be separated physically is a ____________.

pure substance, mixture

__________ has fixed shape and volume.

solid

solid ---> gas gas ---> liquid liquid ---> solid gas ---> solid liquid ---> gas Match the below with the above. -freezing -deposition -condensation -vaporization -sublimation

solid ---> gas = sublimation gas ---> liquid = condensation liquid ---> solid = freezing gas ---> solid = deposition liquid ---> gas = vaporization

__________________ error is caused by equipment or process failure; values are all too high or all too low.

systematic

A mixture contains ___________ or more different substances. A mixture is NOT a pure substance and its components can be separated by _____________ means.

two, physical

Select all that correctly describe the classification of elements. -Elements are generally classified as metals or nonmetals. -All elements are classified as either metals or nonmetals with no exceptions. -Mixtures are generally classified as metals or nonmetals. -The difference between a metal and a nonmetal is based on appearance and properties. -Some elements have properties somewhere between metals and nonmetals.

-Elements are generally classified as metals or nonmetals. -The difference between a metal and a nonmetal is based on appearance and properties. -Some elements have properties somewhere between metals and nonmetals.

Which of the following changes often (but not always) indicates that a chemical change has taken place? -The substance changes from a liquid to a gas. -Energy is released during the process. -The substance is transformed into a different substance which often looks completely different. -The mass of the substance appears to increase during the reaction.

-Energy is released during the process. -The substance is transformed into a different substance which often looks completely different. -The mass of the substance appears to increase during the reaction.

Select all the options that represent chemical properties. -Solubility in water -Flammability -Melting point -Density -Reactivity with water

-Flammability -Reactivity with water

Which of the following options correctly defines heat? -Heat is an increase in temperature. -Heat is the release of energy. -Heat is the transfer of thermal energy. -The heat of an object is its temperature.

-Heat is the transfer of thermal energy.

Which of the following statements concerning density are correct? -If the mass and the density of a pure substance are known, the volume can be calculated for that substance. -In general gases have very low densities because gas particles spread out and occupy large volumes. -A substance with a large mass per unit of volume is less dense than a substance with a small mass per unit of volume. -A solid object with a greater density than a liquid substance will sink in the liquid. -When mercury (density = 13.6 g/mL) and water (density = 1.00 g/mL) are mixed, the mercury floats in the water.

-If the mass and the density of a pure substance are known, the volume can be calculated for that substance. -In general gases have very low densities because gas particles spread out and occupy large volumes. -A solid object with a greater density than a liquid substance will sink in the liquid.

Which of the following options correctly describe the behavior of the phases of matter? -Liquids cannot be compressed by any significant extent. -A solid occupies a fixed volume. -A gas can be compressed. -A liquid has a fixed shape. -A gas occupies a fixed volume.

-Liquids cannot be compressed by any significant extent. -A solid occupies a fixed volume. -A gas can be compressed.

Which of the following options correctly match each element with its symbol? -The symbol for sodium is Fe. -Ni is the symbol for nitrogen. -Pb is the symbol for lead. -The symbol for calcium is Ca. -C is the symbol for carbon.

-Pb is the symbol for lead. -The symbol for calcium is Ca. -C is the symbol for carbon.

Select all that correctly describe a physical state. -Solids, liquids, and gases are examples of physical states of matter. -The arrangement of particles is independent of the physical state of the substance. -The physical state of a substance depends on the identity of the substance and the external conditions applied. -At room temperature, the physical state of any substance is a liquid.

-Solids, liquids, and gases are examples of physical states of matter. -The physical state of a substance depends on the identity of the substance and the external conditions applied.

Select all that correctly describe facts about elements. -Some elements have been synthesized by scientists. -Elements are building blocks of matter -All elements are stable and do not break down over time. -Some elements are isolated from natural sources on Earth.

-Some elements have been synthesized by scientists. -Elements are building blocks of matter -Some elements are isolated from natural sources on Earth.

Select all the options that correctly describe temperature. -Temperature can be measured using a thermometer. -Fahrenheit, Celsius, and Kelvin are all examples of temperature scales. -Temperature is a measure of how hot or cold something is. -Room temperature is the same numerical value regardless of the temperature scale used. -The degree increments os all temperature scales are always the same.

-Temperature can be measured using a thermometer. -Fahrenheit, Celsius, and Kelvin are all examples of temperature scales. -Temperature is a measure of how hot or cold something is.

Which of the following options correctly describe the different types of substances? -The composition of a mixture may vary. -an element contains only one type of atom. -Any time two atoms are bonded together a compound is formed. -A particular compound always contains the same combination of elements.

-The composition of a mixture may vary. -an element contains only one type of atom. -A particular compound always contains the same combination of elements.

Select all the options that correctly describe how energy is involved in chemical reactions. -Chemical energy is kinetic energy arising from the positions of the atoms and molecules in the compounds. -The conversion of energy from one type to another will occur in the process of a chemical reaction. -Some spontaneous chemical reactions release energy. -A compound releases its kinetic energy when it undergoes a spontaneous chemical reaction that forms substances with less potential energy.

-The conversion of energy from one type to another will occur in the process of a chemical reaction. -Some spontaneous chemical reactions release energy.

Which of the following options correctly describe manipulations that may be used to rearrange an equation? -The object of rearranging the equation is to isolate the desired variable on one side of the equation. -Any quantity added to one side of the equation must also be added to the other side. -Any term added to the left-hand side of the equation must be subtracted from the right-hand side of the equation. -If the desired variable is in the denominator, it can be moved to the numerator if its sign is changed. -The desired variable should always end up as the numerator.

-The object of rearranging the equation is to isolate the desired variable on one side of the equation. -Any quantity added to one side of the equation must also be added to the other side. -The desired variable should always end up as the numerator.

What are significant digits in a quantity?

All the reported digits, both certain and uncertain.