CHEM 111
Convert from C to F
(9/5 x T) + 32
Neon has a boiling point of -411 degrees Fahrenheit. Express this temperature in degrees Celsius.
-246 degrees Celsius ((-411 - 32)(5/9)) = -246
Which of the following conversion factors contain only exact numbers? Select all that apply.
1 min = 60 s, 1000 g = 1 kg, 10^3 mL = 1 L
convert 16 nm to um
1.6 x 10^-2 um
when you purchase 0.500 gallon of milk, how many milliliters (mL) of milk are there in the container? (1 gallon = 3.785 L)
1.89 x 10^3 mL (0.500 gal x (3.785 L/1 gal) x (1000 mL/1 L))
A procedure uses 0.0186 L of acetone. If the density of acetone is 0.785 g/mL, what mass of acetone is used?
14.6 g
convert 72 inches (in) to yards (yd) using the conversion factors: 12 in = 1 ft and 3 ft = 1 yd
2 yd
2.5 mm = __________ km
2.5 x 10^-6 km
2.5 cm = _______ um
2.5 x 10^4 um
0.25 m = _______ nm
2.5 x 10^8 nm
An experiment requires 42.5 g of sulfuric acid, which is easier to measure by volume than by mass. What volume in mL should be measured out, if the density of the sulfuric acid is 1.84 g/cm^3?
23.1 mL
A cube of metal measuring 14.2 mm on a side is placed in a graduated cylinder containing 25.3 mL of water. What is the final volume reading in the measuring cylinder? Recall that V = l x w x h and 1 cm^3 = 1 mL
28.2 mL
convert an area of 125 km^2 to m^2, given that 1.609 km = 1 mi
48.3 mi (125 km^2 x (1 mi/1.609 km)^2 = 48.3 mi^2)
Convert from F to C
5/9 x (T - 32)
Which of the following is the correct conversion factor (as written) required to convert a distance of 12 mi to feet, if 1 mi = 5280 ft?
5280 ft/1 mi
which of the following options correctly describe how to convert 65.0 mph to kilometers per second? Select all that apply. 1 mi = 1.609 km.
65.0 mph corresponds to 0.0291 km/s, the factor 1.609 km/1 mi will be used as written in this conversion
The SI system is based on ________ fundamental units called base units. All other units are combinations of these fundamental units and are called _______ units.
7; derived
A student calculates the time taken (in min) for the light from the Sun to reach the Earth. The sun is 93 million miles away (1 mile = 1.609 km) and the speed of light is 3.00 x 10^8 m/s. Select the correct answer, quoted to the correct number of sig figs.
8.3 min, since 9.3 x 10^7 has 2 sig figs
Which of the following statements correctly describe a well-designed, controlled experiment? Select all that apply.
Experimental results must be reproducible for the experiment to be valid, a controlled experiment tests the effect of changing one variable at a time
temperature
Kelvin (K)
Convert from K to C
T - 273.15
True of False: if the number 26.5 is rounded to two significant figures it will be 26
True
Which of the following statements correctly describe the macroscopic view of the three stages of matter? Select all that apply.
a liquid conforms to the shape of its container, a gas conforms to both the shape and the volume of the container it is in, a liquid has a fixed volume.
Which of the following options correctly describe physical and chemical properties? Select all that apply.
a physical property can be observed without a chemical reaction, when a chemical property is measured the substance being observed is converted to a different substance or interacts with another substance.
An extensive property is defined as
a property that depends on the amount of substance present (Mass)
An intensive property is defined as
a property that is independent of sample size (Density)
Which of the following statements correctly define SI base units and derived units? Select all that apply.
all base units are based on metric units, there are 7 base units in the SI system
any units that do not cancel
are the units for the unknown quantity
Which of the following options correctly describe the three temperature scales and their relationship to each other? select all that apply.
both the Kelvin and Celsius scales have the same size degree unit, absolute zero is 0 K or -273.15 degrees Celsius, all temperatures in the Kelvin scale (other than 0 K) are positive.
During a chemical change or reaction, a substance is changed into one or more different substances. The ____________ composition and the physical ______________ of the new substance(s) will be different from those of the original substance.
chemical, properties
which of the following statements correctly describe how conversion factors are used in calculations? select all that apply.
conversion factors are relationships used to express the same quantity in different units, the conversion factor should be selected so that the units in the original quantity cancel with one of the units in the factor, all units should cancel except for those required for the answer when multiplying by a conversion factor
weight
depends on the local gravitational field
Fahrenheit and Celsius
differ in the size of the temperature unit and the zero point
Celsius and Kelvin
differ only in the zero point; the size of the temperature unit is the same
mass
does not change with location
Which of the following statements correctly describe the energy and energy changes in a system? Select all that apply.
energy is defined as the ability to do work, stability is associated with a lower energy of the system, energy is conserved when it is converted from potential to kinetic energy or vice versa.
How do exact numbers affect the significant figures of the answer to a calculation?
exact numbers do not limit the number of significant figures in a calculation.
A number that is part of a unit definition has no uncertainty associated with it and is called a(n) __________________ number. Such numbers do not limit the number of ________________ figures in a calculation.
exact; significant
units can be multiplied and divided, just like numbers. For example 1 ft^3/ft^2 equals 1 ___________ and 1 m^2 is equal to 1 m x _______________.
ft, m
A student carried out an experiment using a circular piece of aluminum foil (of known thickness) to determine the value of pi. The accepted value of pi is 3.1416. The student's results were 3.6689, 3.6687, and 3.6693. Select the best statement about this student's results in regard to precision and accuracy.
high precision and low accuracy
The scientific method is a systematic approach to studying our world. Based on the observations we make, we formulate a(n) _____________ and test it by designing a controlled _________________. The results or __________ collected in this phase will allow us to design further tests and potentially to formulate models and theories to explain the world around us.
hypothesis, experiment, data
An experiment is a set of steps designed to test a(n) __________. A controlled experiment measures the effect of changing one _____________ while keeping all others constant. This allows cause and effect to be established in a systematic way.
hypothesis, variable
mass
kilogram (kg)
Both physical and chemical changes are accompanied by a change in the total energy of the system, which is divided into two broad categories, __________________ energy due to motion and ____________________ energy due to position.
kinetic, potential
every measurement includes some uncertainty, which is usually assumed to be reflected by the __________ digit of the number. all the digits recorded in a measurement are called the _____________ figures of the measurement.
last; significant
The measurement with the ___________ amount of certainty in a calculation sets the limit for the entire calculation and determines the number of ______________ figures in the final answer.
least; significant
Chemistry is the study of matter, which is commonly defined as anything that has __________ and occupies __________.
mass, space
Density is defined as the ratio of ________ to _________ for a substance or sample
mass, volume
amount of substance
mole (mol)
the units of conversion factors
must cancel at each step, except for the units needed for the answer
A special rule is used for rounding a number when the digit removed is equal to 5 or 5 followed only be zeros. In this case, the preceding number increases by 1 if it is __________ and remains unchanged if it is ____________.
odd; even
the known quantities in the problem
often provide useful conversion factors
Chemical Properties
properties that a substance displays as it transforms into or associates with another substance or substances
Physical Properties
properties that can be measured without changing the identity or composition of a substance
a conversion factor is a(n) _________ used to express a quantity in different units of measurement. Multiplying by a conversion factor is the same as multiplying by ______ because the numerator and denominator are equivalent.
ratio, 1
Which of the following statements correctly reflect the rule governing rounding in a calculation? Select all that apply.
rounding is necessary when there are too many digits after a calculation, the least certain measurement determines the certainty of the answer
Volume is the amount of three-dimensional ___________ that any sample of matter occupies. The most common non-SI units used for volume are the liter, symbol _____, and the milliliter symbol ______.
space, L, mL
Which option(s) correctly describes the procedure used to determine the number of significant digits in a reported quantity? Select all that apply.
start at the left and move right until you reach the first nonzero digit, all digits from the first nonzero digit onward (going to the right) are significant if there is a decimal point, and if there is no decimal point we assume that the trailing zeros are not significant unless exponential notation clarifies the quantity
the measure of how hot or cold an object is relative to another is its _____________, whereas _____________ is the energy that flows between two objects
temperature, heat
addition and subtraction
the answer is rounded to have the same number of digits after the decimal as the quantity with the fewest digits after the decimal.
multiplication and division
the answer is rounded to have the same number of significant figures as the quantity with fewest significant figures.
Which of the following statements correctly describe a physical change? Select all that apply.
the chemical composition of the substance is not altered during a physical change, the physical form of the substance changes during a physical change
weight is defined as
the force exerted on an object by the local gravitational field
which of the following options correctly describes weight and mass? select all that apply.
the mass of an object is the amount of matter it contains, an object's weight is a result of a gravitational force, the mass of a given object is constant
the digit removed is greater than 5
the preceding number increases by 1
the digit removed is a 5 followed by only zeros
the preceding number increases by 1 if it is odd and remains unchanged if it is even.
the digit removed is less than 5
the preceding number remains unchanged
mass is defined as
the quantity of matter in an object
A recipe calls for 1/4 cup of butter. One ounce (oz) of butter is equivalent to 2 tablespoons (T), and there are 8 oz of butter in 1 cup. Which of the following statements correctly interpret the information provided? Select all that apply.
the recipe requires 4T of butter, the information provided gives the conversion factor 8 oz/1 cup.
The area of a telescope lens is 7903 mm^2. If a technician takes 45 s to polish an area of 135 mm^2, how long (in hours) does it take to polish the whole lens?
the starting point for the calculation is 7093 mm^2, the problem assumes that the conversion between seconds and hours is known, the information contains the conversion factor 45 s/135 mm^2
A nail is measured with a ruler and its length is reported as 5.46 cm. Select all the statements that are correct about the certainty and uncertainty represented in this recorded measurement.
the uncertainty can be expressed by reporting the measurement as 5.46 +/- 0.01 cm, the uncertainty is in the final digit of the measurement.
Which of the following options correctly reflect the relationship between SI units and units containing decimal prefixes? Select all that apply.
there are 1000 g in one kg, 1 nm = 10^-9 m hence there are 10^9 nm in 1 m.
Which of the following statements correctly describe how units are treated in a mathematical calculation? Select all that apply.
units can be multiplied or divided, like units can be canceled by division, quantities cannot be added or subtracted unless they have like units
the unknown quantity
will be the solution to the problem
the number 0.025349 rounded correctly to 3 significant figures is ____________.
0.0253
25 km = ____ m
25,000 m
Convert from C to K
T + 273.15
What are significant digits in quantity?
all the reported digits, both certain and uncertain
length
meter (m)