Presentation on theme: "Which of the following is/are heterogeneous mixtures? Gasoline Tea Italian salad dressing White wine Vinegar Beach sand Dirt."— Presentation transcript:
Which of the following is/are heterogeneous mixtures? Gasoline Tea Italian salad dressing White wine Vinegar Beach sand Dirt
Which of the following is/are heterogeneous mixtures? Italian salad dressing, Beach sand, Dirt The rest are solutions.
Which of the following processes do not represent chemical changes? Iron rusting Distillation of a liquid Reaction of sodium metal with water Leaves changing color Dissolving sugar in water Filtration of a solid from a liquid
Which of the following processes do not represent chemical changes? Distillation of a liquid, Dissolving sugar in water, Filtration of a solid from a liquid are physical changes. Iron rusting, Reaction of sodium metal with water, Leaves changing color are chemical changes.
Which of the following do not represent physical properties? Boiling point Color Reaction with oxygen Conductivity of gold Burning of gasoline
Which of the following do not represent physical properties? Reaction with oxygen, Burning of gasoline are chemical properties Boiling point, Color, Conductivity of gold are physical properties
Which of the following is/are compounds? Distilled water Iron Milk Air Table salt Aspirin tablets
Which of the following is/are compounds? Distilled water, Table salt are compounds Iron is an element Milk, Air, Aspirin tablets are mixtures
How many g are there in g?
1g = 10 6 g g x (1x10 6 g/1g) = 13,400 g Or 1.34x10 4 g
Which metric prefix would replace the power of ten in 3.68x10 -3 m?
10 -3 is refers to milli, so the number would be 3.68millimeters.
Can a set of measurements be precise without being accurate? Can the average of a set of measurements be accurate even if the individual measurements are imprecise?
Yes, data measurements may be close to one another (precise) but not be close to the accepted value. This type of error usually occurs from a miscalibrated instrument. Yes, if the average of the imprecise measurements happens to be close to the accepted, published value. This is not an acceptable way of data collection however.
Use exponential notation to express each of the following measurements in terms of SI base units. 1.09ng 90.1ms 145pm
Use exponential notation to express each of the following measurements in terms of SI base units. 1.09ng x (1kg/1x10 12 ng) = 1.09x kg 90.1ms x (1s/1x10 3 ms) = 9.01x10 -2 s 145pm x (1m/1x10 12 pm) = 1.45x m
Ray Bradbury chose “Fahrenheit 451” as the title of his novel about book burning in a future society. A firefighter told him that is the temperature at which paper ignites. What would his title have been had be been given the temperature in degrees Celsius?
o C = (5/9)(451 o F – 32) = 233 o C
The highest temperature ever recorded in Phoenix, Arizona was 50.0 o C. Express this in o F?
o F = (9/5) 50.0 o C + 32 = 122 o F
Determine the number of L in a box that measures 4cm x 8cm x 10cm.
= 4cm x 8cm x 10cm = 320cm 3 (raw data) = 3x10 2 cm 3 based on round-off rules. 3x10 2 mL x (1L/1,000mL) =.3L = 3x10 -1 L
Determine the number of significant digits in the following numbers: x
Determine the number of significant digits in the following numbers: x10 6 (5) 45.1(3) (9) (4) 600(1) 500.(3)
A bathroom-type scale is calibrated (marked off) in tenths of a kilogram from 1 to 200kg. Determine how many significant figures should be used to express the mass of anyone using the scale whose mass is between 10 and 99kg.
4 digits are allowed. If the scale is calibrated in tenths, then it is the 100ths place that is uncertain. Based on the allowed digit of uncertainty, this gives a total of four. For example 25.46kg
How many significant figures does the result of the following operation contain?
How many significant figures does the result of the following operation contain? This is addition, and therefore depends on the least number of digits after the decimal point. Since 1.93 only has two, the “raw” result from the calculator ( ) is reported as
If a car has an EPA mileage rating of 30 miles per gallon, what is this rating in km/L?
Magnesium (Mg) and iron (Fe) have densities of 1.7g/cm 3 and 7.9g/cm 3 respectively. If a sample of iron has a mass of 826g, what is the mass of a block of magnesium that has the same volume as the block of iron?
The mass of Mg needed is 826g * (1.7g/cm 3 / 7.9g/cm 3 ) = = 1.8x10 2 g
An irregularly shaped piece of metal with a mass of 125g is placed into a graduated cylinder that contains 25.00mL of water. This raises the water level to 56.00mL. What is the density of the metal?
125g / (56.00mL – 25.00mL) = 4.03g/mL
A student performs a density experiment and achieves the following results: 2.33g/mL 2.32g/mL 2.31g/mL The published value for the density of the object is 2.65g/mL. Comment on the accuracy and precision of the experiment.
A student performs a density experiment and achieves the following results: 2.33g/mL 2.32g/mL 2.31g/mL The published value for the density of the object is 2.65g/mL. Comment on the accuracy and precision of the experiment. The data results are reasonably precise, but not very accurate.
Perform the following conversions to the correct number of significant digits: 642g=_____kg 2.65m 3 =_____cm in=_____cm 94ft=_____m 1.2lb=_____g 248lb=_____kg 1.85gal=_____L
Perform the following conversions to the correct number of significant digits: 642g(1kg/1,000g)=.642kg 2.65m 3 (10 6 cm 3 /1m 3 )=2.65x10 6 cm in(2.54cm/1in)=174cm 94ft(1m/3.281ft)=29m 1.2lb(453.6g/1lb)=5.4x10 2 g 248lb(.4536kg/1lb)=112kg 1.85gal(1L/.2643gal)=7.00L
A fertilizer contains 21% nitrogen by mass. What mass of this fertilizer, in kilograms, is required for an application of 775g of nitrogen?
775g =.775kg.775kg =.21x x = 3.7kg of nitrogen (to the correct number of significant digits)
Calculate the mass of a block of iron (density = 7.86g/cm 3 ) with dimensions of 52.8cm x 6.74cm x 3.73cm.
D = m/Vm = DV (7.86g/cm 3 )(52.8cm x 6.74cm x 3.73cm) = 1.04x10 4 g
Perform the following calculations; express each number and the answer in exponential form with the appropriate number of significant figures. a. b. c.d.
Perform the following calculations; express each number and the answer in exponential form with the appropriate number of significant figures. a. 99,600 = 1.0x10 5 b … = 1.0x10 0 c..4461… = 4.46x10 -1 d..5768… = 5.77x10 -1
You decide to establish a new temperature scale on which the melting point of mercury (-38.9 o C) is 0 o M and the boiling point of mercury (356.9 o C) is 100 o M. What would be the boiling point of water in degrees M? The temperature of absolute zero in degrees M?
The ratio of the two temperature scales are (356.9 o C o C)/(100 o M-0 o M) 1 o M=3.958 o C In addition, the zero point on the M scale = o C. Therefore, o C = o M BP H 2 O = 100 o C = 35.1 o M Ab. Zero = o C = o M
The volume of a red blood cell is about 9.00x cm 3. Assuming that red blood cells are spherical, what is the diameter of a red blood cell in inches?
V = 4/3 r 3 for a sphere Diameter = 2r r = (3V/4 ) 1/3 = 2.78x10 -4 cm Diameter = 2.78x10 -4 x 2 = 5.56x10 -4 cm 5.56x10 -4 cm x (1in/2.54cm) = 2.19x10 -4 in