Chapter 3 - Matter and Energy
A candy bar contains 225 Cal of nutritional energy. How many joules does it contain. Given: 225 Cal Find: joules
1 Cal = 1,000 cal 1 cal = 4.184 J 225 Cal X 1,000 cal/1 Cal = 225,000 cal 225,000 cal X 4.184 J/1 cal = 941400 J = 9.41 X 10^5 joules
Convert 2.75 X 10^4 kJ to calories.
1 kJ = 1,000 J 1 cal = 4.184 J 2.75 X 10^4 kJ X 1,000 J/1 kJ = 27,500,000 J 27,500,000 J X 1 cal / 4.184 J = 6572657 cal = 6.57 X 10^6 cal
A chemist forms 16.6 grams of potassium iodide by combining 3.9 grams of potassium with 12.7 grams of iodine. Show that these results are consistent with the law of conservation of mass.
3.9 g Potassium + 12.7 g Iodine = 16.6 g of Potassium Iodide
An automobile gasoline tank holds 42 kg of gasoline. When the gasoline burns, 168 kg of oxygen are consumed and carbon dioxide and water are produced. What total combined mass of carbon dioxide and water produced?
42 kg gasoline + 168 kg of oxygen = carbon dioxide + water 210 kg
What is a Calorie (Cal)?
A Calorie (Cal) is an energy unit equivalent to 1000 little c calories.
What is a chemical property?
A chemical property are those properties that a substance can display only through changing its composition.
What is the specific heat capacity of Aluminum?
Aluminum = 0.903 J/degrees C
Convert -321 F to kelvins
C = (5/9) * (F - 32) K = C + 273.15 C = (5/9) * (-321 - 32) = -196.1 C K = -196.1 + 273.15 = 77.03 K = 77 K
You find a 1979 copper penny (pre 1982 pennies are pure copper) in the snow and pick it up. How much heat does the penny absorb as it warms from the temperature of the snow, -5.0 degrees C to the temperature of your body 37 degrees C? The mass is 3.1 g. Copper specific heat capacity is 0.385. Given: m = 3.1 g; Ti = -5; Tf = 37; C = 0.385 Find: Heat
Change Temp = 42 Heat = (3.1) * (0.385) * 42 = 50.127 J = 50.1 J
What is the specific heat capacity of Copper?
Copper = 0.385 J/degrees C
Which temperature is identical on both the Celsius and Fahrenheit scales. a) 100 degrees b) 32 degrees c) 0 degrees d) -40 degrees
D) - 40 degrees
What is decanting?
Decanting is separating a mixture by carefully pouring it off.
What is electrical energy?
Electrical energy is energy associated with the flow of electric charge.
What is energy?
Energy the capacity to do work.
What is the specific heat capacity of Ethanol?
Ethanol = 2.42 J/degrees C
Convert 139 degrees C to Fahrenheit
F = (9/5) * (? degrees C) + 32 F = (9/5) * 139 + 32 = 282 degrees F
What is filtration?
Filtration is separating a mixture by pouring the mixture through filter paper usually held in a funnel.
What is the specific heat capacity of Gold?
Gold = 0.128 J/degrees C
Gallium is a solid metal at room temperature but melts at 29.9 degrees C. If you hold gallium in your hand, it melts from your body heat. How much heat must 2.5 g of gallium absorb from your hand to raise the temperature of the gallium from 25 degrees C to 29.9 degrees C. The specific heat capacity of gallium is 0.372 J/g degrees C. Given: 2.5 g; Ti - 25 C; Tf = 29.9 C; C = 0.372 Find: Heat
Heat = (2.5 g) * (0.372) * (29.9 - 25) 4.557 J = 4.6 joules
What it the equation of Heat?
Heat = Mass X Specific Heat Capacity X Temperature Change q = m X C X <>T
The temperature of a lead fishing weight rises from 26 degrees C to 38 degrees C as it absorbs 11.3 J of heat. What is the mass of the fishing weight in grams. Given: Tf = 38; Ti = 26; Heat = 11.3J; C = 0.128 Find: Mass
Heat = mass X specific heat capacity X change in temp Change in Temp = 38 - 26 = 12 11.3 J = mass * (0.128) * 12 11.3 = mass * 1.536 11.3/1.536 = mass = 7.4 grams
What is the specific heat capacity of Iron?
Iron = 0.449 J/degrees C
Convert -25 degrees C to kelvins
K = C + 273.15 -25C + 273.15 = 248.15 K
What is the atomic/molecular motion of a liquid?
Liquid - Free to move relative to one another.
What is matter composed of?
Matter is ultimately composed of atoms.
Consider a drop of water that is put into a flask, sealed with a cap and heated until the droplet vaporizes. Is the mass of the container and water different after heating.
No. In the vaporization, the liquid water becomes gaseous, but it mass does not change also follow the law of conservation of mass.
What are reactants?
Reactants are the initial substances in a chemical reaction, represented on the left side of a chemical equation. Reactants are substances present before the chemical change.
What is the specific heat capacity of Silver?
Silver = 0.235 J/degrees C
What is the shape of a solid?
Solid Shape- Definite
What is the volume of a solid?
Solid Volume - Definite
What is the Celsius scale.
The Celsius scale is a temperature scale often used by scientists. On this scale, water freezes a 0 degrees C and boils at 100 degrees C at 1 atm pressure. Room temperature is appox. 22 degrees C.
What is the Fahrenheit scale?
The Fahrenheit scale is the temperature scale that is most familiar in the United States; water freezes at 32 degrees F and boils at 212 degrees F at 1 atm pressure.
What is the Kelvin scale?
The Kelvin scale is the temperature scale that assigns 0 K to the coldest temperature possible, absolute zero (273 degrees C or -459 degrees F), the temperature at which molecular motion stops. The size of the kelvin is identical to that of the Celsius degree.
What are the common states of matter?
The common states of matter are solid, liquid and gas.
What is the total energy of a sample of matter?
The total energy of a sample of matter is the sum of its kinetic energy and potential energy.
What is volatile?
Volatile is tending to vaporize easily.
What is the specific heat capacity of Water?
Water = 4.184 J/degrees C
What is work?
Work is the result of a force acting on a distance.
Classify each pure substance as an element or a compound. a) aluminum b) sulfur c) methane d) acetone
a) aluminum - element b) sulfur - element c) methane - compound d) acetone - compound
Which of the following properties of ethylene (a ripening agent for bananas) are physical properties, and which are chemical. a) colorless b) odorless c) flammable d) gas at room temperature e) 1 L a mass of 1.260 g under standard conditions f) mixes with acetone g) polymerizes to form polyethylene
a) colorless - Physical Property b) odorless - Physical Property c) flammable - Chemical Property d) gas at room temperature - Physical Property e) 1 L a mass of 1.260 g under standard conditions - Physical Property f) mixes with acetone - Physical Property g) polymerizes to form polyethylene - Chemical Property
Classify each change as exothermic or endothermic. a) water freezing into ice b) natural gas burning
a) water freezing into ice - Exothermic b) natural gas burning - Exothermic
Given: 235 g water; 25 degree C Initial Temp; 100 degree final temp Find Amount of Heat needed (q)
m = 235 g Change T <>T = Tf - Ti = 100 - 25 = 75 degrees C Specific Heat Capacity of Water = 4.184 Heat = (235 g) * (4.184) * 75 = 73743 J = 7.37 X 10^4 J
In a butane lighter, 9.7 g of butane combine with 34.7 g of oxygen to form 29.3 g carbon dioxide and how many grams of water?
9.7 g butane + 34.7 g oxygen = 29.3 carbon dioxide + water 15.1 grams of water
What is a calorie (cal)?
A calorie (cal) is the amount of energy required to raise the temperature of 1 gram of water by 1 degree Celsius.
What is a chemical change?
A chemical change is a change in which matter changes its composition. Matter does change its composition. Matter undergoes a chemical change when it undergoes a chemical reaction.
What is a chemical reaction?
A chemical reaction is the process by which one or more substances transform into different substances via a chemical change. Chemical reactions often emit or absorb energy.
What is a compound?
A compound is a substance composed of two or more elements in fixed definite proportions. Compounds are more common that pure elements. Examples: Water, table salt, and sugar
The complete combustion of a small wooden match produces approx. 512 cal of heat? How many kilojoules are produced? Given: 512 cal Find: kJ
1 cal = 4.184 J 1 kJ = 1000 J 512 cal X 4.184 J/1 cal = 2142.208 J 2142.208 J X 1 kJ/1000 J = 2.14 kJ
Suppose a salesperson wants to make an appliance seem as efficient as possible. In which units does the yearly energy consumption of the appliance have the lowest numerical value and therefore seem most efficient? a) J b) cal c) Cal d) kWh
1 cal = 4.184 J = .001 Cal = kWh is the largest of the four units listed so the numerical value of the yearly energy consumption is lowest if expressed in kWh
How many joules equal 1 kilowatt-hour (kWh)?
1 kilowatt-hour (kWh) = 3.6 X 10^6 joules (J)
Suppose 12 g of natural gas combines with 48 g of oxygen in a flame. The chemical change produces 33 g of carbon dioxide. How many grams of water form?
12 g natural gas + 48 g oxygen = 33 g carbon dioxide + ? water 27 g water
What is specific heat capacity or specific heat?
Specific heat capacity is the heat capacity of a substance in joules per gram degree Celsius (J/g degrees C)
What is exothermic?
Exothermic describes a process that releases heat energy. Chemical reactions that release energy, like the explosion of TNT. In an exothermic reaction, the reactants have greater energy that the products, and energy is released as the reaction occurs.
What is the atomic/molecular motion of a gas?
Gas - Free to move relative to one another.
What is the compressibility of a gas?
Gas Compressibility - Compressibile
What is the shape of a gas?
Gas Shape - Indefinite
What is the atomic/molecular spacing of a gas?
Gas Spacing - Far apart
What is the volume of a gas?
Gas Volume - Indefinite
What is heat capacity?
Heat capacity is the quantity of heat energy required to change the temperature of a given amount of a substance by 1 degree Celsius.
What is heat?
Heat, which has units of energy, is the transfer or exchange of thermal energy caused by a temperature difference.
What is a heterogeneous mixture?
A heterogeneous mixture is a mixture, such as oil and water, that has two or more regions with different compositions.
What is a homogeneous mixture?
A homogeneous mixture is a mixture, such as salt water, that has the same composition throughout.
What is a kilowatt-hour (kWh)?
A kilowatt-hour is a unit of energy equal to 3.6 million joules..
What are the two forms of mixtures?
A mixture can be a homogeneous mixture or a heterogeneous mixture. The majority of matter that we encounter is in the form of mixtures. Mixtures may be composed of two or more elements, two or more compounds, or a combination of both. Examples: apple juice, a flame, salad dressing and soil, air, seawater, brass
What is a mixture?
A mixture is a substance composed of two or more different types of atoms or molecules combined in variable proportions.
What is a physical change?
A physical change is a change in which matter does not change its composition even though its appearance might change. Matter changes its appearance but not its composition.
What is a physical property?
A physical property are those properties that a substance displays without changing its composition.
What are the two forms of a pure substance?
A pure substance can be an element or a compound.
What is a pure substance?
A pure substance is a substance composed of only one type of atom or molecule.
What is an element?
An element is a substance that cannot be broken down into simpler substances.
What are atoms?
Atoms are submicroscopic particles that are the fundamental building blocks of matter. The smallest identifiable unit of an element.
Convert 55 degrees F to Celsius
C = (5/9) * (F-32) C = (5/9) * (55 - 32) 12.8 degree C = 13 degrees C
What is chemical energy?
Chemical energy is energy associated with chemical changes. A form of potential energy associated with the positions of particles that compose the chemical system.
What is distillation?
Distilling is separating a mixture by boiling off miscible liquids.
What is endothermic?
Endothermic describes a process that absorbs heat energy. Chemical reactions that absorb energy form their surroundings as they occur. The reaction that occurs in a chemical cold pack is a good example of an endothermic reaction. In an endothermic reaction, the products have more energy that the reactants, and the energy is absorbed as the reaction occurs.
Given: 212 K Find: Degrees C
K = C + 273.15 212K - 273.15 = -61.15 degrees C
Convert 358 K to Celsius.
K = C + 273.15 358K - 273.15 = 84.85 C
Convert 310 K to Fahrenheit
K = C + 273.15 F = (9/5) * (?C) + 32 C = 310 K - 273.15 = 36.85 C F = (9/5) * (36.85) +32 = 98.33 F = 98 degrees F
What is kinetic energy?
Kinetic energy is energy associated with the motion of an object. The energy associated with its motion.
What is the specific heat capacity of Lead?
Lead = 0.128 J/degrees C
What is the compressibility of a liquid?
Liquid Compressibility - Incompressibile
What is the shape of a liquid?
Liquid Shape - Indefinite
What is the atomic/molecular spacing of a liquid?
Liquid Spacing - Close together
What the volume of a liquid?
Liquid Volume - Definite
What are the two forms of matter?
Matter can be a pure substance or a mixture.
What is matter?
Matter is anything that occupies space and has mass. Anything that occupies space and had mass. Matter exists in three different states: solid, liquid and gas.
What is a molecule?
Molecules are two or more atoms joined to one another in a specific geometric arrangement. Two or more atoms joined in a specific arrangement by chemical bonds. A molecule is the smallest identifiable unit of a molecular compound.
What is potential energy?
Potential energy is the energy of a body that is associated with its position or the arrangement of its parts. The energy associated with its position or composition.
What are products?
Products are the final substances produced in a chemical reaction; represented on the right side of a chemical equation. Products are substances present after the change.
What are properties?
Properties are the characteristics we use to distinguish one substance from another. Different substances have unique properties that characterize them and distinguish them from other substances.
What is the atomic/molecular motion of a solid?
Solid - Oscillation or vibration about a fixed point.
What is the compressibility of a solid?
Solid Compressibility - Incompressibile
What is the atomic/molecular spacing of a solid?
Solid Spacing - Close together
What is the law of conservation of energy?
The Law of Conservation of Energy is that energy is neither created nor destroyed. The total amount of energy is constant; energy can be changed from one form to another or transferred from one object to another, but it cannot be created out of nothing and it does not vanish into nothing.
What is the Law of Conservation of Mass?
The Law of Conservation of Mass states matter is neither created not destroyed in a chemical reaction. During physical and chemical changes, the total amount of matter remains constant even though it may not initially appear that it has.
What is temperature?
The temperature of a substance is a measure of its thermal energy. The hotter the object, the greater the random motion of atoms and molecules that compose it, and the higher the temperature.
What is thermal energy?
Thermal energy the energy associated with the random motions of atoms and molecules in matter. The hotter an object, the more thermal energy it contains.
Perform each conversion. a) 588 cal to joules b) 17.4 J to Calories c) 134 kJ to Calories d) 56.2 Cal to joules
a) 588 cal to joules 1 cal = 4.184J 588 cal X 4.184 J/1 cal = 2460.192 J = 2.46 X 10^3 b) 17.4 J to Calories 1 cal = 4.184 J 1 Cal = 1,000 cal 17.4 J X 1 cal/4.184 J = 4.158699 cal 4.158 cal X 1 Cal/1,000 cal = 0.0041587 Cal = 4.16 X 10^-3 c) 134 kJ to Calories 1 kJ = 1,000 J 1 cal = 4.184 J 1 Cal = 1,000 cal 134 kJ X 1,000 J/1 kJ = 134000 J 134,000 J X 1 cal/4.184 J = 32026 cal 32026 cal X 1 Cal/1,000 cal = 32.03 Cal d) 56.2 Cal to joules 1 Cal = 1,000 cal 1 cal = 4.184 joules 56.2 Cal X 1,000 cal/1 Cal = 56200 cal 56200 cal X 4.184 J/1 cal = 235140.8 J = 2.35 X 10^5 J
Are these data sets on chemical changes consistent with the law of conservation of mass? a) A 7.5 g sample of hydrogen gas completely reacts with 60.0 g of oxygen to form 67.5 g of water. b) A 6.5 g sample of gasoline completely reacts with 243 g of oxygen to form 206 g of carbon dioxide and 88 g of water.
a) 7.5 g hydrogen gas + 60.0 g oxygen = 67.5 g of water - Yes - This is consistent with law of conservation of mass b) 6.5 g gasoline + 243 g oxygen = 206 g carbon dioxide + 88 g water No - This is not consistent with the law of conservation of mass
Classify each change as physical or chemical. a) A balloon filled with hydrogen gas explodes upon contact with a spark b) The liquid propane in a barbecue evaporates away because someone left the valve open c) The liquid propane in a barbecue ignites upon contact with a spark. d) Copper metal turns green on exposure to air and water.
a) A balloon filled with hydrogen gas explodes upon contact with a spark - Chemical Change b) The liquid propane in a barbecue evaporates away because someone left the valve open - Physical Property c) The liquid propane in a barbecue ignites upon contact with a spark. - Chemical Change d) Copper metal turns green on exposure to air and water. Chemical Change
If you want to heat a metal plate to as high a temperature as possible for a given energy input, what metal should you use? (Assume all plates have the same mass) a) copper b) iron c) aluminum d) it would make no difference
a) Copper - Because copper has the lowest specific heat capacity of the three metals, it experiences the greatest temperature change for a given energy input.
Classify each change as physical or chemical. a) Rusting of iron b) the evaporation of fingernail-polish remover from the skin. c) the burning of coal d) the fading of a carpet upon repeated exposure to sunlight
a) Rusting of iron - Chemical Change - Iron rusts because it reacts with oxygen in air to form iron(III) oxide b) the evaporation of fingernail-polish remover from the skin. - Physical Change - When fingernail polish remove evaporates it changes from liquid to gas, but it remains acetone. c) the burning of coal - Chemical Change - Coal burns because it reacts with oxygen in air to form carbon dioxide. d) the fading of a carpet upon repeated exposure to sunlight - Chemical Change - A carpet fades on repeated exposure to sunlight because the molecules that give carpet its color are decomposed by sunlight.
Classify each property as physical or chemical. a) The tendency of silver to tarnish b) the shine of chrome c) the color of gold d) the flammability of propane gas
a) The tendency of silver to tarnish - Chemical Property b) the shine of chrome - Physical Property c) the color of gold - Physical Property d) the flammability of propane gas - Chemical Property
Classify each type of matter as a pure substance or a mixture. If it is a pure substance, classify it as an element or a compound. If it is a mixture, classify it as homogeneous or heterogeneous. a) a lead weight b) seawater c) distilled water d) Italian salad dressing
a) a lead weight - It is a pure substance and an element. b) seawater - It is a mixture. It is a homogeneous mixture. c) distilled water - It is a pure substance and a compound. d) Italian salad dressing - It is a mixture. It is a heterogeneous mixture.
Classify each mixture as homogeneous or heterogeneous. a) coffee b) chocolate sundae c) apple juice d) gasoline
a) coffee - homogeneous b) chocolate sundae - heterogeneous c) apple juice - homogeneous d) gasoline - homogeneous
Classify each change as physical or chemical. a) copper metal forming a blue solution when it is dropped into colorless nitric acid b) a train flattening a penny placed on a railroad track c) ice melting into liquid water d) a match igniting a firework
a) copper metal forming a blue solution when it is dropped into colorless nitric acid - chemical property b) a train flattening a penny placed on a railroad track -physical property c) ice melting into liquid water - Physical Property d) a match igniting a firework - Chemical Property
Classify each process as exothermic or endothermic. a) gasoline burning in a car b) isopropyl alcohol evaporating from the skin c) water condensing as dew during the night
a) gasoline burning in a car - Exothermic b) isopropyl alcohol evaporating from the skin - Endothermic c) water condensing as dew during the night - Exothermic
Classify each substance as a pure substance or a mixture. If it is a pure substance, classify it as an element or compound. If it is a mixture, classify it as homogeneous or heterogeneous. a) helium gas b) clean air c) rocky road ice cream d) concrete
a) helium gas - pure substance - element b) clean air - mixture - homogeneous c) rocky road ice cream - mixture - heterogeneous d) concrete - mixture - heterogeneous
Classify each type of matter as a pure substance or a mixture. If it is a pure substance, classify it as an element or a compound. If it is a mixture, classify it as homogeneous or heterogeneous. a) mercury in a thermometer b) exhaled air c) chicken noodle soup d) sugar
a) mercury in a thermometer - It is a pure substance and an element. b) Exhaled air - It is a mixture. It is a homogeneous mixture. c) Chicken Noodle Soup - It is a mixture. It is a heterogeneous mixture. d) Sugar - It is a pure substance. It is a compound.
Classify each property as physical or chemical. a) the explosiveness of hydrogen gas b) the bronze color or copper c) the shiny appearance of silver d) the ability of dry ice to sublime (change from solid directly to vapor)
a) the explosiveness of hydrogen gas - Chemical Property b) the bronze color or copper - Physical Property c) the shiny appearance of silver - Physical Property d) the ability of dry ice to sublime (change from solid directly to vapor) - Physical Property
Classify each property as physical or chemical. a) the tendency of copper to turn green when exposed to air b) the tendency of automobile paint to dull over time c) the tendency of gasoline to evaporate quickly when spilled d) the low mass (for a given volume) of aluminum relative to other metals.
a) the tendency of copper to turn green when exposed to air - Chemical Property - Copper turns green because it reacts with gases in air to form compounds b) the tendency of automobile paint to dull over time - Chemical Property - Automobile paint dulls over time because it can fade due to sunlight or it can react with oxygen in air. c) the tendency of gasoline to evaporate quickly when spilled - Physical Property - Gasoline evaporates quickly because it has a low boiling point. d) the low mass (for a given volume) of aluminum relative to other metals.-Physical Property - Aluminum's low mas relative to other metals is due to its low density
Classify each change as exothermic or endothermic. a) wood burning in a fire b) ice melting
a) wood burning in a fire - Exothermic - When wood burns it emits heat into the surroundings b) ice melting - Endothermic - As ice melts is absorbs heat from the surroundings.