UNIT: STATES AND CHANGES OF MATTER
Water has a "bent" geometry. Which properties of water create this molecular shape?
Water's oxygen has lone electron pairs that repel each other.
Describe the molecular structure of water, and explain why it is a polar molecule.
Water is a polar molecule due to the uneven distribution of electrons within the molecule. This polarity arises from the differences in electronegativity between the oxygen atom and the hydrogen atoms. Electronegativity is the tendency of an atom to attract electrons in a chemical bond.
Which of these statements are true of water molecules? Check all that apply.
Water molecules are polar. Water molecules undergo hydrogen bonding. Water molecules have a bent geometry.
The melting point is the temperature at region
2
The substance is in both the liquid and the solid phase in region
2
Which number on the graph represents the phase change melting?
2
Considering the chart shown, at what temperature does the substance boil?
2,200ºC
The substance is in only the liquid phase in region
3
The boiling point is the temperature at region
4
Which number on the graph represents the phase change boiling?
4
Complete the statements by writing the number from the graph. The substance is in the gas phase only in region
5
For which applications would you choose a liquid over a gas or solid?
Washing clothes Linking a brake pedal to the brake pads at the wheels of a car Dissolving sugar Painting a wall
Water's molar mass is 18.01 g/mol. The molar mass of methanol is 32.01 g/mol. At room temperature, water is 64% more viscous than methanol. Which substance has the stronger intermolecular attraction?
Water
Use the information in the table to describe the temperature-vs.-time diagrams. Which number on the graph represents a solid?
1
According to kinetic-molecular theory, which of the following would not be considered an ideal gas? Check all that apply.
A gas at very low volumes, when gas particles are very close together A gas at very low temperatures, when gas particles have very little kinetic energy A gas with highly polar molecules that have very strong intermolecular forces
Identify the examples of diffusion in the list below. Check all that apply.
A teacher takes the cap off a permanent marker. A few minutes later, students at the back of the classroom complain about the odor of the marker. A cooking school student burns a piece of toast. Soon, the entire kitchen smells like burnt toast. Toxic fumes produced by a chemical factory are detected in the air in a town several miles away.
Nitrogen (N2) or ammonia (NH3):
Ammonia
glass
Amorphous
rubber
Amorphous
Which image best represents the particles in liquids
B
Liquid nitrogen becomes a gas when it is poured out of its container. The nitrogen is
Boiling
_______ can conduct electricity.
Both solids and plasmas
Gasoline and motor oil are chemically similar. They are both mixtures of nonpolar hydrocarbons containing carbon and hydrogen atoms. However, motor oil is much more viscous than gasoline. Which substance probably has the higher average molar mass?
Motor Oil
In a lab, methane and nitrogen are cooled from -170°C to -200°C. The methane freezes and the nitrogen _______
Condenses
Water vapor in the air becomes tiny liquid droplets that form fog. The water is
Condensing
Energy is released during which phase changes? Check all that apply.
Condensing Depositing Freezing
Classify the below solids as amorphous or crystalline. emerald
Crystalline
MgCl₂
Crystalline
Dissolving salt in water reduces the intermolecular forces between water molecules. What most likely happens to the surface tension of water when salt is dissolved in it?
Decreases
Which of these changes most likely results in an increase in the volume of a gas?
Decreasing the pressure on the gas
In a very cold cryogenic freezer, solid oxygen forms on the walls from the oxygen gas in the air. The oxygen is
Depositing
Which of the following could be classified as matter? Check all of the boxes that apply.
Desk Water Cloud Helium
Test your knowledge of water's ability to dissolve substances by matching the following statements with the correct answers. when water breaks apart an ionic compound into cations and anions:
Dissociation
when water breaks down substances and surrounds individual molecules or particles:
Dissolving
Which of these did your answer include?
Each hydrogen atom is bonded to the oxygen atom with a single bond. The oxygen atom has two lone pairs. The molecule is bent. Oxygen is more electronegative than hydrogen. Each O-H bond is polar. The molecule is asymmetrical. The asymmetry and the polar bonds produce an overall molecular dipole. The oxygen atom has a partial negative charge, and the hydrogen atoms have a partial positive charge.
Fluorine (F2) or chlorine (Cl2):
Fluorine
Identify each of the phase changes described below. Liquid gold is poured into molds and cools to become solid bars. The gold is
Freezing
Can you use melting point to determine the identity of an unknown solid? The metal is observed to begin to melt when the temperature of its container is approximately 29°C. The metal is most likely _______
Gallium
Use the table to answer the questions below. When the temperature in a room increases from 25°C to 33°C, _______ changes from a solid to a liquid.
Gallium
When gold is heated to 2,856°C it changes from a liquid to a
Gas
Imagine the movement of gas particles in a closed container. According to the kinetic molecular theory, which statements below are true of the gas particles? Check all that apply.
Gas particles act like tiny, solid spheres. Gas particles are in constant, random motion. Collisions are elastic, there is no energy lost as the particle hits the sides of the container.
Recall the postulates of kinetic-molecular theory. Read the list and check all the statements that apply to the behavior of an ideal gas:
Gas particles behave like hard spheres Gas particles travel randomly Average kinetic energy of a collection of gas particles depends on the temperature
Which of these substances most likely dissolve in water? Check all that apply.
Glucose, a polar organic compound Silver nitrate, an ionic compound
Both hydrogen sulfide (HS) and ammonia (NH) have strong, unpleasant odors. Which gas has the higher effusion rate?
NH 3
A chef is using honey in a recipe. The honey is too thick to pour out of the jar. How could the chef make the honey easier to pour?
Heat it
Water's strong hydrogen bonds result in which physical properties? Check all that apply.
High boiling point High specific heat Density of ice being less than that of liquid water
Which unusual properties are a result of water's hydrogen bonding? Check all that apply.
High boiling point High specific heat High surface tension
when water surrounds substances that have been "broken apart":
Hydration
Which processes are involved when water dissolves sugar? Check all that apply.
Hydration Increase of the surface area of the solute
For each pair of gases, select the one that most likely has the highest rate of effusion. Use the periodic table if necessary. Oxygen (O2) or hydrogen (H2):
Hydrogen
A sample of gas is enclosed in a container of fixed volume. Identify which of the following statements are true. Check all that apply.
If the container is cooled, the gas particles will lose kinetic energy and temperature will decrease. If the gas particles move more quickly, they will collide more frequently with the walls of the container and pressure will increase. If the gas particles move more quickly, they will collide with the walls of the container more often and with more force, and pressure will increase.
The diagrams to the right show the distribution and arrangement of gas particles in two different containers. According to kinetic-molecular theory, which of the following statements is true? Check all that apply.
If the temperatures of both containers are equal, container A has greater pressure than container B. If the pressure in both containers is equal, container A has a lower temperature than container B.
City A is located along the shore of an ocean. City B is at the same latitude and altitude, but it is located about 124 miles (200 km) inland, away from any large bodies of water. Which of the following statements most likely describe these two cities? Check all that apply.
In the summer, the daytime temperature in City A is typically lower than the daytime temperature in City B. In the winter, the daytime temperature in City B is typically lower than the daytime temperature in City A.
A container with a specific volume "V" changes to "2V." What happens to the average distance between gas molecules? Assume that pressure and temperature of the gas remain constant.
Increase
Water readily dissociates ionic compounds, dissolves polar covalent molecules, and hydrates the smaller particles. This is most likely because water
Is a polar molecule
The attraction forces between mercury atoms in liquid mercury are stronger than the intermolecular forces between water molecules. Which of the following is most likely true about mercury?
It has a higher surface tension than does water.
Pure maple syrup has a high sugar content. Its composition is 70% sucrose (CHO). If you heat maple syrup what will happen to its viscosity?
It will decrease.
A sample of a gas is placed inside a cylinder that is a fixed size. The cylinder is heated as additional gas is added to it. What will most likely happen to the pressure of the gas inside the cylinder?
It will increase
Which statements are true based on specific heat? Check all that apply.
Land heats up/cools down faster than water. Regions with moderate climates often have large bodies of water surrounding them.
Solid iron is heated to high temperatures so that it becomes a liquid. The iron is
Melting
Methane (CH4) or carbon tetrachloride (CCl4):
Methane
Which statements describe phase changes? Check all that apply.
Particles in a liquid need to move more slowly in order to freeze. Attractive forces between the particles in a liquid are broken when a liquid boils.
________ particles have very high velocities.
Plasma
Which functions of water in living systems would still be possible if water was not polar and did not form hydrogen bonds? Check all that apply.
Providing body support by exerting pressure on cell walls Providing body support through buoyancy Transport of nutrients within organisms
Identify which properties could correspond to solids, plasmas, or both. _________ maintain a unique shape.
Solids
_______ typically have a low temperature.
Solids
Which of the following are examples of plasmas?
Stars Auroras A neon sign
In the high desert, snow changes to water vapor without becoming liquid water. The snow is
Subliming
Suppose you were given a substance and asked to determine whether it was a plasma. What characteristics would be true of the substance for it to be a plasma? Check all that apply.
The particles in the substance would collide more often. The particles in the substance would have high kinetic energy. The substance would be composed of ionized particles.
A chemist is studying the properties of a gas under various conditions. He observes that when the gas is at room temperature and low pressure, it behaves as an ideal gas. When the gas is cooled to 10 kelvin (-263ºC) and is placed under high pressure, however, it deviates significantly from an ideal gas. There are multiple reasons for this phenomenon. Check all of the correct reasons below.
The ideal gas model assumes that gas particles experience no intermolecular attractions and these forces cause the gas to deviate from ideal behavior. At very low temperatures, gas particles move slowly. At very high pressures, gas particles are very close together.
A student places a small amount of water in a glass dish and then carefully places a small paperclip on the surface of the water. The paperclip floats. What happens if the student adds a drop or two of dish soap to the water? Check all that apply.
The paperclip falls through the water to the bottom of the dish. The soap acts as a surfactant. The soap decreases the surface tension of the water.
A student checks the air pressure in her bicycle tires early in the morning when it is cool outside. If she measures it again later in the day when it is hotter, what will she most likely observe?
The pressure has increased.
Which statement describes how phase changes can be diagrammed as a substance is heated?
The temperature is on the y-axis and the time is on the x-axis.
Which property of liquids creates a meniscus in glass tubes as seen in the picture?
adhesion
Which substance most likely has the highest boiling point?
calcium chloride (CaCl2), an ionic compound
What is the movement of water up a narrow tube due to attractions with the surface of the tube called?
capillary action
Determine whether each statement is a description of a physical property or a chemical property. Paper burns readily in air.
chemical
Determine whether each statement is a description of a physical property or a chemical property. Sodium metal reacts vigorously with water to produce hydrogen gas.
chemical
What is the attraction between molecules within a substance called?
cohesion
Which substance would you most likely need to cool to the lowest temperature before it condenses?
ethane (C2H6), a nonpolar covalent compound
Length
extensive
Volume
extensive
Consider a mixture of oil and water. What terms would you use to describe this mixture? Check all that apply.
heterogeneous immiscible
Which of the following set of properties is most likely for a liquid with large, attractive intermolecular forces?
high melting point and high boiling point
Gases Quiz
https://quizlet.com/863731302/gases-quiz-flash-cards/?new
Liquids Quiz
https://quizlet.com/863735063/liquids-quiz-flash-cards/?new
Solids and Plasmas Quiz
https://quizlet.com/863737634/solids-and-plasmas-quiz-flash-cards/?new
Phase Changes Quiz
https://quizlet.com/863740687/phase-changes-quiz-flash-cards/?new
Properties of Water Quiz
https://quizlet.com/863743553/properties-of-water-quiz-flash-cards/?new
Hardness
intensive
Which of the following properties are intensive, and which are extensive? Check the box that applies. Malleability
intensive
What force in liquids causes surface tension?
intermolecular forces
A comparison often made between solids and plasmas is based on their densities. How would you describe the density of a plasma?
low density
How would you describe the kinetic energy of the particles in a solid?
low kinetic energy
Alcohol has a sweet odor.
physical
Determine whether each statement is a description of a physical property or a chemical property. Please check the box that applies. Copper conducts heat well.
physical
Determine whether each statement is an example of a physical change or a chemical change. Paper is shredded.
physical
Salt is a solid.
physical
Steel is attracted to magnets.
physical
Water (H2O) is a liquid at room temperature. Ammonia (NH3) is a gas at room temperature. Both are polar covalent compounds. Which compound most likely has the strongest intermolecular forces?
water
