(Ch.3) Matter and Energy Flashcards
What is the definition of energy?
Energy: Besides matter, energy is the other major component of our universe. Like matter, energy is con- served—it can be neither created nor destroyed. Ener- gy exists in various different types, and these can be converted from one to another. Some common units of energy are the joule (J), the calorie (cal), the nutritional Calorie (Cal), and the kilowatt-hour (kWh). Chemical reactions that emit energy are said to be exothermic; those that absorb energy are said to be endothermic.
**(Capacity to do work)
What are three common units for energy?
Joules, calories, Kilowatt-hour
What is an endothermic reaction? Which has greater en-
ergy in an endothermic reaction, the reactants or the
products?
An endothermic reaction is one that absorbs energy from the surroundings. The products have more energy than the reactants in an endothermic reaction.
List three common units for measuring temperature.
Celsius, Fahrenheit, Kelvin
Explain the difference between heat and temperature.
Heat is the transfer of thermal energy caused by a temper- ature difference, whereas temperature is a measure of the thermal energy of matter.
What is heat capacity?
Heat capacity is the quantity of heat energy required to change the temperature of a given amount of the sub- stance by 1 °C.
Why are coastal geographic regions normally cooler
in the summer than inland geographic regions?
the high heat capacity of the seawater keeps the temperature in the city from dropping. In the winter, the ocean actual- ly helps to keep the city warmer, compared to an inland cities.
Formula for Celsius temperature to Kelvin temperature.
K = °C + 273
Classify each mixture as homogeneous or heteroge- neous.
(a) coffee
(b) chocolate sundae
(c) apple juice
(d) gasoline
a. homogeneous c. homogeneous
b. heterogeneous d. homogeneous
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. chemical c. physical
b. physical d. chemical
Determine whether each change is 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 the user 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. chemical c. chemical
b. physical d. chemical
Define matter
Matter is defined as anything that occupies space and possesses mass. It can be thought of as the physical mate- rial that makes up the universe.
What is matter composed of?
Atoms or molecules
What is the difference between a crystalline solid and an amorphous solid?
In a crystalline solid, the atoms/molecules are arranged
in geometric patterns with repeating order. In amorphous solids, the atoms/molecules do not have long-range order.
What is a mixture?
A mixture is two or more pure substances combined in variable proportions.
What is a pure substance?
Pure substances are those composed of only one type of atom or molecule.
What is an element? A compound?
- An element is a substance that cannot be broken down into simpler substances.
- A compound is a substance composed of two or more elements in fixed definite proportions.
What is the difference between a mixture and a com-
pound?
A mixture is formed when two or more pure substances are mixed together; however, a new substance is not formed. A compound is formed when two or more ele- ments are bonded together and form a new substance.
What is the definition of energy?
Energy is defined as the capacity to do work.
Expain the difference between kinetic energy and
potential energy.
Kinetic energy is the energy associated with the motion of an object. Potential energy is the energy associated with the position or composition of an object.
What are three common units for energy?
Three common units for energy are joules, calories, and kilowatt-hour.
What is an endothermic reaction? Which has greater en-
ergy in an endothermic reaction, the reactants or the
products?
An endothermic reaction is one that absorbs energy from the surroundings. The products have more energy than the reactants in an endothermic reaction.
Explain the difference between heat and temperature.
Heat is the transfer of thermal energy caused by a temper- ature difference, whereas temperature is a measure of the thermal energy of matter.
Heat capacity is the quantity of h
What is heat capacity?
Heat Capacity: The temperature change that a sample of matter undergoes upon absorption of a given amount of heat is related to the heat capacity of the substance composing the matter. Water has one of the highest heat capacities, meaning that it is most resistant to rapid temperature changes.