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QOA science final

QuestionAnswer
Suspension: a liquid mixture in which particles can be seen and easily separated by filtration or settling
How is a solute different then a solvent in a solution? the solute is present in a smaller amount
Weak tea is an example of dilute solution
How can a scientist safely tell whether an unknown solution is salt or sugar in water? by testing the electrical conductivity
Saturated Solution: when you add so much solute that no more dissolves
What is one way to increase the solubility of sugar in water? heat the water
How would a solute affect the boiling point of water? the water will boil at a higher temperature
When a solute is added to a solvent, the freezing point of the solution is lower than the freezing point of either substance alone
What is characteristic property of acids? turn blue litmus paper red
Acids are described as corrosive because they "eat away" at other materials
Acids naturally present in food are safe to eat because they usually are weak
You can find the pH of a substance by using litmus indicator
a mixture containing particles that are too small to be seen easily but are large enough to scatter a light beam is called a base
Neutralization is a reaction between acid and a base
What does a neutralization reaction produce? bases
Digestion breaks down complex molecules of food into smaller particles
What is the difference between chemical digestion and mechanical digestion? chemical digestion requires enzymes
How is pH important during digestion? different enzymes work best at different pH values
Normal rainfall is slightly acidic, which means its pH must be between 5 and 7
When a solid compound dissolves in water, each of its particles becomes surrounded by water molecules
Solubility: a measure of how well a solute can dissolve in a solvent at a given temperature
solute: a substance that is present in a solution in a smaller amount and is dissolved by the solvent
What are factors that affect the solubility if a solvent? pressure, the type of solvent, and temperature
What are the characteristic properties of bases and acids? Acids: taste sour, react with metals and carbonates, and turns blue litmus paper red Bases: tastes bitter, feels slippery, and turns red litmus paper blue
what is the product of a neutralization? salt
neutralization: reaction between an acid and a base.
concentration:
Solvent: part of the solution that is present in the largest amount
dilute solution: a mixture that has only a little solute dissolved in a certain amount of solvent.
colloid: mixture containing small, undissolved particles that do not settle out.
concentrated solution: one that has a lot of solute dissolved in the solvent
unsaturated solution: when you can continue to dissolve more solute
example of a colloid: milk, fog
Which can conduct an electric current salt water or sugar water? salt water
What happens when an ionic solid mixes with water? water molecules surround each particle.
What happens when a molecular solid mixes with water? the solute breaks down and into individual molecules
what happens to the solute's particles whenever a solution forms? They leave each other and become surrounded by particles of the solvent.
How do you measure the concentration of a solution? you compare the amount of solute to the amount of the solvent
Which is more soluble in water, baking soda or sugar? sugar
The higher the pressure of the gas, the________gas can dissolve in a solvent. more
Extra info about acids and bases: 1. most solids become more soluble as the temperature goes up 2.most gases become less soluble as the temperature goes up 3. Carbon Dioxide dissolves better in cold water than in hot water.
What is neutral, acidic and basic on the pH scale? neutral: pH of 7 acidic:lower than pH of 7 basic: higher than the pH of 7
Extra info about strengths of acids and bases: 1. a strong base produces more OH- ions than a weak base 2.a strong acid produces more H+ ions than a weak acid
Amylase: an enzyme that helps break down the starchy carbs into smaller sugar molecules
Amylase works best when the pH is near 7
Where does the most chemical digestion take place? small intestine
Carbon is able to bond with atoms of other elements in many different ways because it has four valence electrons
An element whose atoms can make straight chains, branched chains an rings is carbon
Which form of pure carbon is so hard that it can be used in cutting tools? diamond
Which form of pure carbon is formed of layers that slide past one another? graphite
what is another name for carbon compounds? organic compounds
Starch is an example of a complex carbohydrate
What can tell you about methane(CH4)from its molecular formula? it contains four hydrogen atoms
Which compounds have the same molecular formula but different structures? isomers
Which class of organic compounds stores the most energy, gram for gram? lipids or fats
A substituted hydrocarbon that contains one or more hydroxyl groups is called an alcohol
Substances that provide the energy and raw materials that the body needs are nutrients
Which term describes the breaking down of polymers, such as starch or proteins, into monomers the body can use digestion
Proteins are nutrients used in the body mostly for building and repairing body parts:)
What factor determines the primary differences among living things the order if nucleotides in their DNA
What nutrients needed by the human body are NOT organic compounds? minerals
A carbohydrate is made up of the elements carbon and hydrogen, plus oxygen
What is the maximum possible number of hydrogen atoms on a carbon chain called? saturated hydrocarbon
Compounds that contain only the elements carbon and hydrogen are called hydrocarbons
What property do all hydrocarbons have? they burn easily
What shapes do hydrocarbons NOT form? geodesic domes
What is a property of many organic liquids? they have strong odors
What is the shape of pure carbon fullerenes? hollow ball with a pattern like a geodesic dome
How many chemical bonds can each carbon atom form? four
Polymer: a very large organic molecule made up of chains of small molecules
The classes of organic compounds found in all living things are halogen compounds, alcohols, organic acids, and esters.
The simplest kind of carbohydrate is sugar
true or false: Your body can digest starch, but another common complex carbohydrate, cellulose, passes through your body undigested true
What are polymers called that are produced in factories instead of by living things called? synthetic
What are amino acids? building blocks that make up proteins
Minerals: elements needed by the human body
What is lead mostly made of? graphite
Do organic compounds conduct electrical currents? no
What are hydrocarbons only made of? carbon and hydrogen
Carbon atoms can bond with other__________and with atoms of other elements in many different ways. carbon atoms
substituted hydrogen a molecule with an atom of another elements carbon and hydrogen
organic compound a compound that contains carbon
ester the compound that results when an alcohol and an organic acid are chemically combined
polymer very large molecule made of many smaller molecules bonded together
hydroxyl group -OH
structural formula the smaller molecules that make up a polymer
hydrocarbon a compound containing only the elements carbon and hydrogen
alcohol a substituted hydrocarbon with one or more hydroxyl groups
carboxyl group -COOH
monomer the smaller molecules that make up polymers
organic acid a substituted hydrocarbon with one or more carboxyl groups
What are the properties of carbon? mix poorly with water and are flammable
Isomers: compounds that have the same chemical formula but different structual formulas.
saturated hydrocarbon A hydrocarbon in which all the bonds between carbon atoms are single bonds
unsaturated hydrocarbon a hydrocarbon in which one or more of the bonds bewtween carbon atoms is double or triple
substituted hydrocarbon atoms of other elements replace one or more hydrogen atoms in a hydrocarbon.
What are the three ways carbon atoms bond to form the backbones for molecules? straight, ring, chain
Why can the element carbon exist in different forms? it can bond in a lot of other ways
Diamond crystal, hard, used for jems and cutting stone
graphite ring shaped, soft, slippery, used for pencils and lubricants
Fulerene hollow sphere, enclose an open area, possibly carries medicines through the body
nanotube long, hollow tube, extremely strong, conductors in electronic devices
How does a diamond form? under heat and alot of pressure
Why are many organic compounds liquid or gas at room temperature? they have low melting points and low boiling points
What are the names of the 3 hydrocarbons that have molecules made of chains of carbon atoms? methane, propane, ethane
What does a structural fromula show about a molecule of a compound? kind, number, and arrangement of atoms in a molecule.
Each dash in a structural fromula represents a chemical bond
saturated hydrocarbon: singles bonds, ends in -ane example:ethane
unsaturated hydrocarbon: double or triple bonds, ends in -ene or -yne, example: ethene
example of synthetic polymer: polyester, nylon.
plastics synthetic polymers that can be molded or shaped
composites they combine 2 or more substances in a new material with different properties
____________is a synthetic composite made of glass fibers and liquid plastic Fiber glass
What are the four classes of polymers found in all living things? carbs, lipids, PROTEIN :), nucleic acids
Why is glucose sometimes called "blood sugar"? the body circulates glucose to all body parts to blood.
Complex carb a large chainlike molecule made of simple carbs
Proteins polymers formed from smaller molecules called amino acids
When an object's distance from another object is changing, it is in motion
The basic SI unit of length is the meter
Speed equals distance divided by time
When you know both the speed and direction of an object's motion, you know the velocity
You can show the motion of an object on a line graph in which you plot distance agaist time
The steepness of a line on a graph is called the slope
On an acceleration graph showing speed versus time, a straight line shows the acceleration is constant
If you know a car travled 300 kilometers in 3 hours, you can find its average speed
The rate at which velocity changes is called acceleration
If the spped of an object does NOT change, the object is traveling at a constant speed
Changing direction is an example of a kind of acceleration
Average SPeed is the total distance traveled divided bt the total time
If an object moves in the same direction and at a constant speed for 4 hours, what is true? the objects's velocity did not change
A place or object used for comparision to determine if something is in motion is called a reference point
On a graph showing distance versus time, a horizontal line represents an object that is not moving at all
The SI is used all over the world
If you know the distance an object has traveled in a certain amount of time, you can determine the acceleration of the object
Motion is measured realtive to a reference point
Instantaneous speed the rate at which and object is moving at a given instant time.
velocity speed in a given direction
A straight diagonal line on a distance-verus-time graph indicates_________speed constant
A horizontal line on a distance versus time graph mean that an object is at constant speed
What is the SI unit for velocity meter per second per second
What does a straight line mean on a speed versus time graph? constant acceleration
The SI unit for speed is meter
The formula for speed is distance/time
A rider finshes a 10-km bicycle trip in 2 hours. The average speed of the rider is 5 km/hr
A velocity tells speed and direction
A runner starts a 5 km race at 10:15 am. She finsihes at 10:45. With this info you can calculate the runners average speed
You can calculate the slope of a graph line by dividing rise over run
The rate at which velocity changes is acceleration
To find a objects acceleration, you need to know its starting speed, its starting speed, its ending speed, and time
Speed versus time graph a straight line is constant and a slanted line means the object is accelerating at a constant speed
Distance versus time graph: a curved line means that the object is accelerating
What is an example of exerting force? answers may very. ex: a carpenter hammering a nail
What happens when two forces act in the same direction? They add together
The tendency of an object to resist change in its motion is known as inertia
The greater the mass of an object to resist change in its motion is known as the greater its inertia
The force of gravity on a person or object on the surface of a planet is called weight
One way to increase acceleration is by decreasing mass
The force that one surface exerts on another when the 2 rub together is called friction
What is an example of rolling friction bike tires on the road as you ride
When the only force acting on a falling object is gravity, the object is said to be in free fall
Air resistance is a type of friction
The force of gravity on a person or an object at the surface of the planet is known as weight
The law of universal gravitation states that any 2 objects in the universe, with out exception, attract each other
Forces can be added together only if they are acting on the same object
The product of an objects mass and velocity is called its momentum
According to the law of conservation of momentum, when 2 objects collide in the absence of friction, momentum is not lost
The achievement of lifting a rocket off the ground and into space can be explained by Newton's 3rd law
What is required for a rocket to lift off into space? thrust that is greater than Earth's gravity
An object that travels around another object in space is called satellite
Any force that causes an object to move into a circle is called centripetal force
In physical science, a push or a pull, is called a force
The momentum of an object is in the same direction as its velocity
How can you increase the momentum if an object? by increasing its mass
The amount of matter in an object is called its mass
What is an example of increasing friction intentionally? throwing sand on an icy driveway
The force that pulls falling objects through air experience a type of friction called air resistance
According to Newton's 3rd law of motion, when a hammer strikes and exerts force on a nail, the nail exerts equal force back onto the hammer
The SI unit for force is the newton
Balanced forces acting on an object never change the objects motion
The total momentum of a group of objects is conserved unless outside forces act on the objects
t or f: Unbalanced forces do not change an objects motion FALSE
Newton's first law of motion: an object at rest will remain at rest and an object moving at a constant velocity will continue moving at a constant velocity, unless acted upon by an unbalanced force
Newton's second law of motion: acceleration depends on the objects mass and net force acting on the object
Newton's third law of motion: if one object exerts a force on another object, then the second object exerts a force of equal strength in the opposite direction on the first object.
law of conservation of momentum: in the absence of outside forces, the total momentum of objects that interact does not change
static friction the friction that acts on objects that are not moving
Sliding Friction occurs when 2 solid surface slide over each other
Rolling Friction: occurs when an object rolls across a surface
Fluid friction: occurs when a solid object moves through fluid
What does friction depend on? types of surfaces and how hard the surfaces push together
What is the SI unit for momentum? kg.m/s
A force is described by its strength and direction
When the forces acting on an object are balanced the net force of the object is exactly 0
Friction acts in the opposite direction as motion
The amount of gravity between objects depends on their masses ans the distance between them
A__________causes an objects motion to change unbalanced force
What law says that forces come in pairs? newtons third
What affect the gravitational attraction? mass and distance
The unit of force,newton, is equal to kg.m/s2
Snowshoes enable a person to walk on deep snow because increase the area over which the persons weight is distributed
a unit of pressure is called a pascal
Air pressure exerted equally in an object from different directions is balanced pressure
Why doesn't pressure crush you? pressure inside your body balances the air pressure outside ur body
Air pressure decreases as elevation increase
Water pressure increases as depth increases
Which type of substance does Pascals priciple deal with fluids
One application of pascals principle is a hydraulic car lift
Plastic bottle when squeezed...which principle? Pascals
What does a hydraulic system do? multiply force
What direction does a bouyant force act in? Upward
If an object floats, the volume of displaced water is equal to the volume of the portion of the object that is submerged
What scientific rule states that the buoyant force on an object is equal to the weight of the fluid displaced by the object? archimedes principle
Smoke rises up a chimney because of bernoullis principle
Bernoulli's principle helps explain flight
The mass per unit of volume of a substance is its density
Pressure can be measured in newtons per square meter
Which scientific rule states that the pressure exerted by a moving stream of fluid is less that than the pressure of the surrounding fluid? Bernoulli's principle
Created by: kenna42298