Science final study 2015
Terms in this set (220)
The mass of matter per unit of volume.
How is density expressed or described
in units of grams per milliliter, grams per cubic centimeter or kilograms per cubic meter.
Formula for Density is
D = M/V
An example of a compound
An example of a mixture
The atmosphere is a mixture of oxygen and nitrogen
What is the chemical formula for two atoms of oxygen and threee atoms of iron (Fe?)
How many atoms of chlorine (Cl) are in the carbon tetrachloride molecule (CCl4)?
The measure of the upward force that a fluid exerts on an object that is submerged
The buoyant force is equal to the weigh of the fluid displaced by an object..
List three physical properties for a piece of wood
density, volume, mass, color, phase or strength
One cubic centimeter is the same volume as one _________
Explain two ways to find the volume of a plastic cube
1. Measure length x width x thickness or 2. Use displacement method by putting cube in the water. The measure how much water was displaced and then take amount of displaced water and subtract that from the total water.
A certain material has a density of .2 grams per milliliter. Is this material better for building a bridge or making cushions for a couch?
This would be better material for a couch because it is not dense enough to be used to build a bridge and this material would be softer.
The density of a gas is lower than the density of a liquid because___________
because atoms in a gas are farther apart than atoms in a liquid
Density is a _____ property of matter.
Density is the _____ per unit volume of a substance
What measurements must be known in order to find the density of a substance?
mass and volume or the dimensions for calculating the volume of a regular solid
The buoyant force of on an object depends on the ____ of the object that is under water.
What happens to the buoyant force on an object as it is lowered into the water?
It increases because more water is displaced.
The buoyant force on an object is equal to the weight of the water it ________________.
When the buoyant force on an object is greater than it's weight, the object__________.
Floats or rises in the fluid.
Solid iron has a density of 7.9 grams per cubic centimeter. Liquid mercury has a density of 13.5 grams per centimeter per cubic centimeter. Will iron float or sink in the mercury
The iron will float in the mercury because it is less dense.
Why is it incorrect to say that heavy objects sink in water.
Heavy is just a physical property. Density determines whether or not an object will float by doing the calculation to determine if the ratio of mass and volume. An object whose density is less than one will float in water no matter what the mass is.
Steel is denser than water and yet steel ships float. Explain?
The ship is not a solid piece of steel. Because of the way the ship is shaped, most of the ship's hull encloses air. The ratio of the total mass of a ship, divided by the total enclosed volume of the ship is less than the density of the water in which it floats. The average density of enclosure we identify as the ship is than the density of the water. There fore the ship floats.
A temperature scale in which water freezes at 32 degrees and boils at 212 degrees
A temperature scale in which water freezes at 0 degrees and boils at 100 degrees.
An instrument that measures temperature.
Energy that an object possesses due to the temperature
Scattered equally in all direction
Lowest possible temperature at which energy is as close to zero as it can be (-273 Celsius)
A temperature scale that starts at absolute zero and has units the same as Celsius degrees.
A phase of matter that holds its shape and does not flow.
A phase of matter that flows easily and changes shape.
A phase of matter that flows and also expands or contracts to fill any container.
The forces Between atoms or molecules that determine the phase of matter.
Temperature at which melting or freezing occurs
Temperature at which boiling or condensation occurs
thermal energy that is moving or is capable of moving
The amount of energy required to raise the temperature of 1 kilogram of a substance by 1 degree Celsius. Knowing the specific heat tells how quickly the material will change as it gains or loses energy?
the transfer of heat by the direct contact of particles of matter
when things are at the same temperature and no heat flows
the transfer of heat by the motion of matter, such as by moving air or water.
Electromagnetic waves produced by objects because of their temperature
What are the temperatures for Celsius and Fahrenheit related to freezing and boiling point?
boiling 212 degrees f and 100 degrees Celsius freezing 32 degrees f and o degrees c
convert Farenheit to Celsius
T (F)= 9/5t+32
how molecules move in each state of matter, how they hold their shape, and their ability to flow or not flow.
the molecules slow down when you take away heat. changes from a liquid to solid.
thermal energy, heat, & temperature are related. Explain each one & make connections between them.
thermal energy is the sum of energy of molecules, heat is thermal energy transfered, temperature is the measure of thermal energy
What is a thermistor
A thermistor is a type of resistor whose resistance varies significantly with temperature, more so than in standard resistors. The word is a portmanteau of thermal and resistor.
convection, conduction and radiation
What are the means for transferring energy?
The state of two or more objects or substances in thermal contact when they have reached a common temperature
What are the units of heat & thermal energy
Celsius, Fahrenheit and kelvin
How does a line graph show when matter changes states
When ice is changing to water there is a rise in temperature when it is ice. When it is ice and water the temperature stays the same and the temperature changes again on the line graph when the matter turns completely to water. When heat energy is added or subtracted from matter either the temperature changes of the phase changes but usually not both at the same time.
What objects have low specific heat?
Steel and pie crust
What objects have high specific heat?
Water and apple pie filling
Why do different materials have specific heat related to their molecular arrangements?
This is because the temperature measures the average kinetic energy per particle. Heavy particles mean fewer particles per kilogram. Energy that is divided between fewer particles means more energy per particle and therefor not temperature change.
How does heat flow by conduction?
Place a cold spoon into hot cocoa. The molecules in the cocoa have a higher average kinetic energy than those of the spoon. The molecules in the spoon exchange energy with the molecule in the cocoa through collisions. The molecules within the spoon itself spread the energy up the stem of the spoon through the inter-molecular forces between them. Heat conduction works both through collision and also through inter-molecular forces between molecules.
How does heat flow by convection?
Bubbles from on the bottom and rise to the top. Hot water near the bottom of the pan circulate up forcing cooler water near the surface to sink. This circulation carries heat through the water. The transfer process is how the heat flows.
How does heat flow by radiation?
This comes from the thermal energy of atoms. The power in thermal radiation increase with higher temperatures because of the thermal energy of atoms increases with the temperature. Because the sun is extremely hot, It's atoms emit lots of thermal radiation. Unlike conduction or convection , thermal radiation can travel through the vacuum of space. All the enrgy that the earth receives from the sun come from this energy type.
How does thermal equilibrium happen?
As collisions continue the molecules of the hotter material lose energy and the molecules of the cooler material gain energy. The kinetic energy of the hotter material is transferred, one collision at a time, to the cooler material. Eventually, both materials are at the same temperature. This occurs when both materials are at the same temperature. No heats flows in exchange because the temperatures are the same.
What is the difference between insulators and conductors?
One conducts heat easily and the other conducts heat poorly.
How do objects omit and absorb radiation?
Thermal radiation is absorbed by objects. An object constantly receives thermal radiation by everything else in its environment. Otherwise all objects would eventually cool down to absolute zero by radiating their energy away. The temperature of an object rises if more radiation is absorbed. The temperature falls if more radiation is emitted. The temperature adjust s until there is a balance between radiation absorbed an emitted.
The smallest unit of electric charge that is possible in ordinary matter; represented by the lower case letter "e."
A particle with an electric charge (-e) found inside of atoms but outside the nucleus
The tiny core at the center of an atom containing most of the atoms mass and all of it positive charge
A particle found in the nucleus with a positive charge exactly equal and opposite to the electron
a particle found in the nucleus with mass similar to the proton but with zero electric charge.
the number of protons in the nucleus of an atom. The atomic number determines what element that the atom represents.
Atoms of the same element that have different numbers of neutrons in the nucleus
The number of protons plus the numbers of neutrons in the nucleus
a nucleus is stable if it stays to together
a nucleus is radioactive if it spontaneously breaks, emitting particles or energy ion the process.
The characteristic colors of light given off or absorbed by an element.
A bright colored line in a spectrascope
An instrument that separates light into a spectrum
One of the discreet allowed energies for electrons in an atom
The theory that describes matter and energy at small (atomic) sizes.
It is impossible to know variables exactly in the quantum world
The set of rules that are obeyed by every detail of everything that occurs in the universe.
A well-tested explanation for a wide range of observations or experimental results.
List the steps of the scientific method
1. Problem 2. Research 3. Hypothesis 4. Experiment 5. Analyze data 6. Conclusion
Convert Celsius to Farenheit
In a graduated cylinder, it is the curve in the upper surface of a liquid close to the surface of the container or another object, caused by surface tension. It can be either convex or concave, depending on the liquid and the surface.
The calculation for Volume of a rectangle is
L x W x H
The calculaton for volume of a spehre is
What is density not dependent on __________________
The four forces inside inside an atom are
1. Strong nuclear force
2.The elctro magnetic forces
3. The weak nuclear force
Calculation for heat energy
Mass X temp change X Specific heat
What does the Ph scale tell you about different solutions?
it tells the acidity and Ph levels of the solution.
What does the litmus paper tell you about different solutions?
Litmus paper tells you if the solution is an acid or a base (alkaline)
how are the Ph scale and litmus paper similar and different?
They both tell whether each solution is an acid or not. One only tells whether its an acid or not (litmus) and the other also tells the Ph (Ph scale)
What happens when red litmus paper is placed in an acid? when its placed in a base?
When red litmus paper is in acid it stays the same. in a base it turns blue
What happens when blue litmus paper is placed in a base? when its placed in an acid?
blue litmus paper in a base stays blue. In an acid it turns red
What are the 5 signs that there was a chemical reaction in our 6 different reactions?
Bubbles, Precipitate, temperature,color,light
what is an endothermic reaction ? What is an exothermic reaction? what is a precipitate?
feels cold, absorbs energy (endo) heats up, releases energy (exo)
What is conservation of mass?
The mass of the reactants equals the mass of the products
Why didnt the experiment support conservation of mass
The substances were either lessened or made larger, thus breaking the idea of conservation of mass.
What could what could you do to support conservation of mass if gas is formed in the product.
Measure the mass of the gas and the leftover substances
A starting material in a chemical reaction
A chemical substance formed as a result of a chemical reaction
a way to describe a chemical reaction using chemical formulas and other symbols
Chemical transformation or change; the interaction of chemical entities.
A number placed in front of a formula in an equation to indicate the number of molecules of a substance
a substance that includes more than one type of element and/or compound that are not bonded together.
A pure substance made of only one kind of atom
a substance whose smallest particles include more than one element chemically bonded together
Is anything that takes up space and weighs something (has mass.)
made from simple chemical substances known as elements
The smallest piece of an element
How many natural occurring elements on earth
are made of two or more atoms that have combined.
most _____ are made of combinations of atoms from several elements
When two or more elements have combined.
molecules in a ______ are very close together and vibrate in place.
Molecules in a _______ are touching each other but can move about
Molecules in a ________ are spread far apart and move rapidly
Most of the matter that you see, such as water or salt, exists in the form of ___________
If you increase the ________, molecules will move faster.
a bond formed between atoms through the sharing or transferring of electrons
a type of chemical bond formed by shared electrons
a group of atoms held together by covalent bonds
identifies the number and the elements of each type of atom in a compound.
An atom that has an electron charge different from zero
a bond that transfers an electron from one atom to another
a mixture of two or more substances that is uniform at the molecular level
a solution of two or more solids
the component of a solution that is present in the greatest amount
any component of a solution other than the solvent
to separate and disperse a solid into individual particles in the presence of a solvent
The amount of solute that can be dissolved in a specific volume of solvent under certain conditions
A substance is insoluble in a particular solvent if it does not dissolve in that solvent
a solution is saturated if it contains as much solute as the solvent can dissolve
The ration of solute to solvent in a solution.
occurs when a solution has the maximum concentration of dissolved solute
having a concentration greater than the maximum solubility and is unstable
describes a molecule that has charge seperation like water.
Examples of solutions
vinegar and water
An example of an alloy
Types of mixtures
Heterogeneous and Homogeneous
Mixtures in which different substances can easily distinguished
A mixture in which two or more substances are uniformly spread out.
How to increase surface area
Breaking up a solid into powder allows more solvent to come into contact with solute
Increase temperature speeds up causing the to bump each other breaking apart and coming into contact with the solvent.
maximum amount of a solute that can be dissoved in a given amount of solvent at a temperature
The percent of a solute in a solvent per the solutions volume
Concentrated large amounts of solute in a solvent
Dilute small amounts of solute in a solvent
concentration levels of solutions
saturated unsaturated supersaturated
able to dissolve in more solute at a given temperature
The substance that dissolves particles in a solution is called the __________
The substance that is dissolved in a solution is called ______________
A mixture of two or more substances that is uniform at the molecular level is called a(n)_____
A solution of two or more metals is known as a(n)___________
Two protons and two neutrons
A water molecule is an example of a(n) molecule
water is a polar molecule
A region of space around the nucleus where an electron is likely to be found.
Electron moving around a nucleus
What would happen to the solubility of potassium chloride in water as the water temperature increased from 25 degrees Celsius to 75 degress Celsius
The solute would be easier to dissolve.
What are two ways to increase the dissolving rate of sugar in water?
stirring the sugar and increase the surface area (smash it)
Water is described as polar molecule because
it has a positive and negative pole
Water is a solvent in which solution?
saline salt solution
What does PPM stand for?
Parts per million
How would fish in a lake be affected if large amounts of hot water from a factory were released into the lake.
The fish in the lake would move downward nearer to the cold water.
When you open a can of room temperature soda, why is it more likely to fizz than a can that has been refrigerated?
The colder the drink is,
What happens to a supersaturated solution when more solute is added?
the excess solvent will be pushed out
solution for concentration
mass of solute/total mass of solution x100%
the following are solutions:
steel, ocean water, 24-karat gold, orange soda.
the following is not a solution:
muddy water. (not individual molecules, still has clumps of dirt)
the solvent and solute for saltwater is _______
water and salt
the solvent and solute for seltzer water is ______
seltzer tablets and water
the solvent and solute for lemonade made with powder mix is _______
powder lemonade and water
give an example of a solution in which the solute is not a solid and the solvent is not a liquid
sterling silver is liquid silver and other parts metal
when can you say that a solute has dissolved
when the solution is saturated.
describe exactly how you would make 100 grams of a saltwater solution that is 20% salt. in your description, tell how many grams of salt and how many grams of water you would need.
why is water often called the universal solvent?
The way water is constructed makes it a great way to dissolve powders and smaller solids like sugar and salt. it has a positive and a negative pole
what is the difference between a compound and a mixture?
A compound is multiple chemically bonded atoms and a mixture is
Give one example of a compound and one example of a mixture
O2Fe3 (compound) saltwater (mixture)
how many atoms of Chlorine are in the carbon tetra chloride molecule CCl 4?
write a chemical formula for a compound that has two atoms of oxygen and three atoms of iron.
how many atoms of hydrogen are in a molecule of acetic acid
chemical bonds form because:
the atoms have _____ energy bonded together than separated
the action or process of moving or being moved
the property of matter by which it retains its state of rest or at constant velocity along a straight line so long as it is not acted upon by an external force. Primary manifestation (demonstration) of mass.
The forces pushing (or pulling) an object in one direction are the same size as the forces acting in the opposite direction. Net Force = 0;
a body of coherent matter, usually of indefinite shape and often of considerable size
Something that does work or causes a change
When the forces on an object are pushing harder in one direction than in another, causing movement. Net Force ≠ 0
the speed of something in a given direction. Units m/s
increase in the rate or velocity of something. Units m/s^2
The natural force of attraction between two objects.
First Law of Motion
An object at rest will remain at rest unless acted upon by an unbalanced force.
Newton's second law
Force is the product of mass and acceleration
Newton's third law
For every action there is an equal and opposite reaction
length to cover over a period of time
amount of land or anything moved in a given time
The rate at which an object is moving at a given moment in time.
speed that stays the same. moving at a constant speed means that you travel the same distance each second.
the total distance divided by the total time per trip
force pulling all objects down or towards it.
positive and negative acceleration
positive acceleration adds more speed each second: things get faster. Negative acceleration subtracts some speed each second: things get slower (deceleration)
Why different elements emit different color flames.
electrons emit photons. Each element has a unique arrangement of electrons.
balanced chemical equation
chemical equation with the same number of atoms of each element on both sides of the equation
a force that resists motion
keeps an object that is standing still (at rest) from moving.
a force that resists dry sliding motion between any two surfaces
Friction that occurs when an object rolls over a surface.
Friction that occurs as an object moves through a fluid.
friction cause by air on an object.
The curved path an object follows when thrown or propelled near the surface of the Earth.
Any force that causes an object to move in a circular path
calculation for velocity
V= D/T plus direction
calculation for acceleration
change in speed/change in time
formula for force
Force = mass x acceleration
formula for mass
M = Density x Volume
formula for free falling objects
V=time x gravity (9.8m/s^2)
accelerated motion that happens when an object falls with only the force of gravity acting on it.
acceleration due to gravity
the value of 9.8 m/s^2, which is the acceleration in free fall at the earth's surface, usually represented by the small letter g
All the digits that can be known precisely in a measurement, plus a last estimated digit. It is importan
significant figures importance
they represent the full number that is being found and show precision.