# Chemistry - Gases ( second note package )

Flashcards by Kastania, updated more than 1 year ago
 Created by Kastania almost 6 years ago
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## Resource summary

 Question Answer What does Pressure measure? Pressure measures how often molecules collide with one another Pressure measures how often ____ collide with one another Molecules What measures how often molecules collide with one another? Pressure In how many ways can pressure be increased? 2 What can be increased in two ways? Pressure What are the 2 ways pressure can be increased? Pressure can be increased 1) moving the molecules closer together 2) increasing the speed at which the molecules travel to make collisions more frequent What is the type of relationship between pressure and volume ? Pressure and volume have an inverse (opposite) relationship Pressure and volume have an _____ relationship between them Inverse ( opposite ) As volume increases, what happens to pressure? pressure decreases As pressure decreases, volume ______ Increases If pressure increases, what happens to volume? Volume decreases If volume decreases, pressure _____ Pressure increases What did Boyle and other scientists determine about the relationship between pressure and volume? They determined that the relationship between pressure and volume was constant at a given temperature and amount, of any gas. If temperature and the number of moles of a gas stay the same, which formula can be used? P1V! = P2V2 When can the formula P1V1 = P2V2 be used? It can be used when the temperature and amount of moles of a gas stay the same What is the symbol for Pressure? P The formula P1V1 = P2V2 can be used as long as temperature and the number of moles of a gas __________ as long as they stay the same When the Celsius temperature scale was created it was based off of 2 numbers, what are those numbers? the freezing point of water = 0 & the boiling point of water = 100 What is the symbol for Volume? V What does temperature measure? it measures how much energy a substance has What measures how much energy a substance has? Temperature ________ is a measure of how much energy a substance has Temperature in order for scientists to use temperature as a part of their mathematical calculations a new _________ ____ was needed Temperature scale a new temperature scale was created so scientists could what? So they could use temperature in their mathematical calculations. Would a change in 1 degree be the same energy change in this new scale as it was the Celsius scale? Yes 0 degrees on the Kelvin scale would represent the point, at which what happens? The point at which all atomic motion stops What degree on the Kelvin cycle represents the point at which all atomic motion stops? 0 degrees How was the Kelvin scale created ? It was created by observing the relationship of volume and temperature in gasses. By observing the relationship of volume and temperature in gasses, a scale was created. what is that scale? The kelvin scale What is the Combined Gas law It is a way to express the relationships between temperature, pressure, and volume at any fixed amount of gas What is the new scale called ( the one used in calculations ) The Kelvin Scale It was found that at -273.15 degrees all gasses would theoretically have no ______ no Volume At what degree was is it found that all gasses would theoretically have no volume? at -273.15 degrees celsius What does Charles law require? It requires that both the amount of the gas and the pressure of the gas remain constant Was -273.15 degrees used as 0 degrees to create the kelvin scale? yes To convert Kelvin to Celsius, ________ Subtract 273.15 To convert from Celsius to Kelvin______ Add 273.15 At sea level what is the average atmospheric pressure ? 101. 325 kPa also known as ! atm Charles' Las only applies when what? When temperature has been measured in degrees Kelvin Mathematically Charles' Law formula is ..............? V1 / T1 = V2 / T2 Whose laws are combined to form the Combined Gas Law? Boyle's and Charles What does the combined gas law express? It expresses the relationships between temperature, pressure and volume at any fixed amount of gas Formula for Combined Gas Law is? P1 V1 / T1 = P2 V2 / T2 What are scientific laws and theories? they are explanations of the evidence that scientists have collected What are laws in science? They are observations and often only true in certain conditions Often laws are well comfiermend _________ statments Factual Formula to calculate moles ? n = V / Vm What do theories explain? They explain the mechanisms behind laws they are true in a wide range of situations and they have been repeatedly confirmed Charles Law As one increases the other ___ ________ proportionally As one increases the other also increases proportionally Neither laws nor theories are " _______ " Scientific guesses Do theories and laws change when new evidence comes to light that they cannot account for? yes they do Before laws and theories can be accepted their must be what? Supporting evidence Each state of matter has different types of ______ in its particles Motion Charles Law The relationship between volume and temperature is a direct relationship Solids have ________ motion Vibrational What type of motion does a solid have? Vibrational Motion Liquids have _____ , ________ , & __________ motion Vibrational Rotational Translational What types of motions do liquids have? They have vibrational, rotational, and translational Gases have _____ motion translational What type motion do gases have? Translational Fluids can flow, since ______ motion allows them to move past each other translational Translational? In a straight line from one spot to another without interruption What 4 things must an acceptable theory do? 1) describe observations in terms of non-observable ideas 2) explain existing evidence 3) predict results of future experiments 4) be as simple as possible in concept and application Gases can be ______ until translational motion becomes vibrational compressed How can a gas be changed into having a vibrational motion instead of a translational motion? By compressing the gas Vibrational Stays in one spot and vibrates very very little Rotational stays in same spot, only re- ordinates itself Because real gases behave slightly different from ideal gases, the numbers predicted by PV=nRT will be slightly______ slightly off, but usually the difference is insignificant what does the law of combining volumes state? It states that when measured at the same temp & pressure, volume of gaseous reactants and products of chemical reactions are always in simple ratios of whole numbers Who proposed a further explanation for volume ratios in terms of number of molecules Amedeo Avagadro What does Avogadros' theory propose? It proposes that equal volumes of gases at the same temp and pressure contain equal number of molecules All gases at a specific temp and pressure must be a certain volume- molar volume- that contains ___ _____ __ ___ One mole of particles Molar Volume? Is the volume that one mole of gas occupies at a specified temp and pressure SATP molar volume is _________ 24.8 L/mol STP molar volume is ______ 22.4 L/mol Symbol for molar volume ? Vm In real gases what happens when temperature decreases ? Molecules slow down until intermolecular forces are able to condense them into liquids When a gas is being compressed so it can change into vibrational motion, what happens ? The gases pressure increases until collisions occur constantly Does an ideal gas condense into a liquid when cooled? No In real gasses as pressure increases what happens to the molecules? They are forced close together, making their size similar to the distancse between them What type of velocity do ideal gases move at? They move at a constant velocity in a straight line with no intermolecular forces Are Ideal gasses far apart or close together ? They are very far apart, so the size of their molecules is meaningless Ideal Gas? An ideal gas is a hypothetical gas that obeys all the gas laws perfectly under all conditions In real gasses does the shape change when molecules collide? Yes the shape changes slightly when molecules collide, slowing it down what formula do we use when temperature, pressure, volume and chemical amount/matter are connected P V = n R T What is R ? It is the universal gas constant at 8.314 When particles collide in ideal gasses is energy lost? No energy is lost when particles collide and the molecules shape doesn't change making the collision totally elastic significant difference usually only occurs when? when the gas is close to becoming a liquid

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