Exam 1 Study Guide
There are about 5.3×10^−6kg of quartz in a very fine sand grain. Write the number of kilograms of quartz in the sand grain in standard notation.
0.0000053 kg
Round the measurement 0.424 to two significant figures.
0.42
What is 498 mm in m?
0.498 m
An object has a mass of 25.0 g and displaces 42.5 mL of water. What is the density of the object, in grams per milliliter? Your answer should have three significant figures (round your answer to three decimals places).
0.59 g/mL
Multiply 2.334 cm and 0.320 cm. (Remember to consider significant figures.)
0.747 cm^2
A liter is equivalent to:
1 dm^3
How many meters are in a kilometer?
1000
The prefix pico (p) means:
10^-12
The speed of light is around 6.706×10^8 miles per hour. What is the speed of light in units of miles per minute?
11176666.667 miles per minute
Which of the following is true?
A law is formed when testing yields constant observations.
Which of the following factors used in a dimensional analysis calculation have a finite number of significant figures (in other words, they are not exact numbers) that might limit the precision of the calculated value?
A measurement of speed equaling (27.7 km/hour)
Units of measurement provide which of the following?
A standard comparison of measurements
Which of the following best describes a scientific theory?
A theory is a comprehensive explanation for observed phenomena, and is generally backed up by many scientific experiments.
If you are asked to report a temperature in base SI units, which scale might you use?
Kelvin
What is conducted in order to test the validity of a hypothesis?
An experiment
Doctors must understand how hormones are synthesized in the body in order to provide adequate medical information. What science is central to the understanding of hormone synthesis and balanced chemical reactions?
Chemistry
Which phenomenon requires chemistry to understand?
Digestion, medicine, and technology
A proposed and testable explanation for an observation is known as a:
Hypothesis
A tentative explanation of observations that acts as a guide for gathering and checking information is called a:
Hypothesis
Characterize the following statement: If you drink coffee before going to bed, it will take longer to fall asleep.
Hypothesis
Ice cubes float at the top of sodas and other drinks. What explains this phenomenon?
Ice cubes are less dense than the sodas and drinks they can be found in.
A pattern that has been established based on verified experimental data that describes an observation but does not provide an explanation as to the reason why said observation occurs is a _________.
Law
A statement that summarizes a vast number of experimental observations without providing a satisfactory and comprehensive explanation is called a:
Law
Which best characterizes the following statement: Energy is never created nor destroyed.
Law
In some cases, volume can be found by cubing which of the following quantities?
Length
Chemistry is the study of:
Matter, energy, and transformation
Which of the following is NOT a base unit of SI?
Ounce
What is the SI unit for measuring time?
Second
Which of the following is true regarding temperature?
Temperature is an intensive property.
In the study of chemistry, you will learn about the ideal gas law, which relates pressure, temperature, and volume for gases. What is the best reason why the ideal gas law is studied in chemistry?
The ideal gas law explains how the properties of gases change.
What is the standard SI unit of mass?
The kilogram
When reading a measurement from an analog instrument like a ruler or a mercury thermometer, how should you determine the number of significant figures to record?
The least significant figure should be estimated by reading between the smallest markings on the instrument.
Select the statement that best completes the following sentence: __________________ sets science apart from other methods of discovery.
The process of experimentation
Which of the following statements is true?
Theories attempt to explain observations.
A hypothesis that provides a way to predict a particular phenomenon and has been subjected to rigorous testing and validating to become accepted by scientists is known as which of the following?
Theory
A well-substantiated, comprehensive, testable explanation of a particular aspect of nature is called a(n):
Theory
Characterize the following statement: All life on earth evolved by natural selection from a common ancestor.
Theory
True or false: In science, a theory is best defined as "a well-supported, comprehensive, and testable explanation of an aspect of the natural world."
True
True or false: the study of science has been organized into multiple fields, because it is too multifaceted to be studied as a whole.
True
The unit cubic meters is associated with:
Volume
How does the scientific method begin?
With an observation
A scientific theory is best described as:
a comprehensive, substantiated, and testable explanation of how nature works
In November 2018, the kilogram was redefined in terms of Planck's constant. Until this time, the kilogram was based on:
a cylinder of platinum-iridium alloy
Density is a(n):
intensive property
What does density measure?
mass per volume
Which of the following is the first step of the scientific method?
observation and curiosity about the natural world
The oil settles on the surface of the water after an oil spill because:
oil is less dense than water
A temperature change of one degree kelvin is the same magnitude as a change of
one degree Celsius
Which is the shortest length of time?
one nanosecond
Volume is the:
space occupied by any sample of matter
Chemistry is best defined as the study of which of the following?
the properties and interactions of matter
If a hypothesis is shown to be accurate after multiple tests, then:
there is still a chance that it could be proven wrong
Which has a greater mass, 1 kg of rocks or 1 kg of feathers?
they will be equivalent
If a scientist wanted to determine the amount of space occupied by an object, she would measure its:
volume
Chemistry often involves working with chemical reactions, like the one shown below, which describes the decomposition of carbonic acid when a soda can is opened. What does this equation mean? H2CO3(aq)→H2O(l)+CO2(g)
The carbonic acid, H2CO3, changes into water, H2O, and carbon dioxide, CO2.
A graduated cylinder initially contains 48.6 mL water. When a piece of jewelry is submerged in the graduated cylinder, the total volume increases to 61.2 mL . What is the volume of the piece of jewelry?
12.6 cm^3
Which of the following has 3 significant figures? Select all that apply.
123 12.3 1.23×10^4
Place the following steps of the scientific method in the correct order. 1. Hypothesis becomes theory. 2. Curiosity leads to observations. 3. Experiment is performed and results are consistent with prediction. 4. Hypothesis is created. 5. Additional testing is conducted and it supports hypothesis.
2, 4, 3, 5, 1
The label on a soft drink bottle gives the volume in two units: 2.0 L and 67.6 fl oz. Use this information to derive a conversion factor between the English and metric units.
2.0 L/67.6 fl. oz.=0.030 L/1 fl. oz.
A cube with a mass of 250.0 g has sides measuring 5.00 cm each. What is the density of this cube in grams per cubic centimeter?
2.00 grams per cubic centimeter
Stephanie added 2.334 mL of water to a beaker, and she then added another 0.31 mL of water to the same beaker. How much water was in Stephanie's beaker? (Remember to consider significant figures in your answer.)
2.64 mL
What is 0.29 km in mm?
290,000 mm
Saltwater covers approximately 361,900,000 square kilometers of the earth's surface. Write the number of square kilometers of saltwater in scientific notation.
3.619 x 10^8 square kilometers
If we wish to convert a value in years into days, a conversion factor we could use would be:
365 days/1 year
450 m/110 s equals which of the following values to the correct number of significant figures?
4.1 m/s
If you are traveling at 49.00 miles per hour, what is your speed in feet per second? (1 mile=5280 ft)
49.00miles/hour×1hour/60 min×1 min/60 seconds×5280 feet/mile=71.87feet/sec
The coating on a pair of eyeglasses is about 0.5μm thick. Give this thickness in meters.
5 x 10^-7 m
When determining significant figures within a number, non-zero digits are:
Always significant
The temperature of an object is independent of the size of the sample. In other words, temperature is:
An intensive property
Why is chemistry known as the "central science"?
Because it intersects with and provides a basis for a variety of other scientific disciplines.
How many minutes are there in exactly 180 days?
Begin by starting with the value of 180 days and multiply by a fraction that is equal to one that we are already aware of: 180 days×24 hours/1 day When we multiply this value of 180 days by this fraction, we can see that the units cancel, just like an algebraic variable: 180 days×24 hours/1 day We repeat this process with different conversions, until we end up with the desired unit of minutes, and then we perform all of the calculations. 180 days×24 hours/1 day×60 minutes/1 hour=259,200 minutes
In geology, we study the atoms that make up stone and soil, which determine the hardness, erosion, and physical qualities of the landscape. What science is used to understand the composition of these stones?
Chemistry
Why is chemistry important?
It helps us explain other aspects of science. It is the central science. We use it to study both small and large aspects of our universe.
Choose the best explanation below for why dimensional analysis is also sometimes referred to as the factor label approach.
It is sometimes called the factor label approach because units are treated as a factor (along with a numeric factor) in a quantity like 25g, allowing us to subject the unit to algebraic operations as if they were variables.
What would happen to the block if it had a density of 0.500 kg/L and was placed in the same 100.0 L tank of water?
It would float.
The temperature scale we use most frequently in chemistry is:
Kelvin
Object A has a density of 2.0 g/cm3 and a mass of 100 g. Object B a density of 0.8 g/cm3 and a mass of 240 g. Object C a density of 5.0 g/cm3 and a mass of 100 g. Which of the objects above (A, B, or C) has the least volume?
Object C
The number of significant figures in a value is a display of the _________ of a measurement.
Precision
The measurement 35 degree C is equal to what temperature in kelvin?
Recall that the conversion from temperatures in ∘C to K is TK=T∘C+273.15. Substitute in the known values and solve. TK=35+273.15=308.15 K The answer should have three significant figures, so round to 308 K.
Which of the following is a rule of significant figures in calculations?
Round down if the digit to be dropped is less than 5.
Which of the following is a rule for determining significant figures in calculations involving addition and subtraction?
Round the result to the same number of decimal places as the starting term with the lowest number of decimal places.
0.738×0.28 is 0.20664 but is rounded to 0.21. Which rule or rules are applied to this calculation?
Round the result to the same number of significant figures as the value with the least number of significant figures. Round up if the digit to be dropped is 5 or greater.
Metals can rust when exposed to oxygen atoms found in air or water molecules. Why does rusting fall under the study of chemistry?
Rusting is an example of an interaction of matter.
The international metric system used in science, medicine, and industry is known as:
SI
The lifetime of a human is approximately 71 years. Which of the following is this number closest to? Remember the following conversion factors: kilo (10^3), mega (10^6), giga (10^9), and tera (10^12).
Taking an average of 71 years and converting into seconds gives: 71 years×365 days/year×24 hours/day×60 minutes/hour×60 seconds/minute=2,239,056,000 seconds Rounding to two significant figures and writing it in scientific notation gives 2,239,056,000 seconds≈2.2×109 seconds. Reviewing the values of the prefixes, the exponential factor, 109, can be replaced by "giga," which is the only prefix that has the correct order of magnitude (maximum place value). 2.2×109 seconds=2.2 gigaseconds
If ice floats on liquid water, then the density of ice is:
less than that of liquid water
Which prefix means one one-hundredth?
centi
What is the volume of a 5.30g piece of aluminum? The density for aluminum is 2.70g/mL.
d =m/v v =m/d v =5.30 g/2.70gmLv =1.96mL
Carbon dioxide has a density of 2.0g/L. What mass will a 3.5 L sample of carbon dioxide have?
m =d×v 2.0g/L×3.5 L= 7.0g
What is the density of a 37.2 mL sample of sulfuric acid weighing 63.8 g, in grams per milliliter?
d= m/v d=63.8g37.2mL d=1.72 g/mL
A student drops a 5.00 kg block into a tank containing 100.00 L of water. The block sinks to the bottom of the tank and the water level rises to 101.25 L. What is the density of the block?
density=mass/volume=5.00 kg/1.25 L=4.00 kg/L
For a number written in scientific notation, a×10^b, a is called the __________.
digit term or mantissa
Which would NOT be an appropriate unit for density?
g/s
If object A and object B have the same density, but object A has greater mass, then object A must have:
greater volume
The SI unit for mass is the:
kilogram