the density of a substance is equal to the mass (amount of matter) of the substance divided by the volume of the substance. Density is an intrinsic property that does not change with the amount of materieal. Three different liquids with different densities were placed together in a container as shown. The liquids, when sirred and allowed to resettle, returned ot the same arrangement.
liquid 1 has a higher density than liquid 2
archimedes' principle states that an object placed under water displaces a volume of water equal to its own volume.
If a boy has a pile of small rocks of the same composition and he wants to determine the density (mass/volume) of the rocks, which combination of devices should he use?
a balance, a supply of water and a large graduated (measuring) cylinder
gases consist of molecules of specific substances. For instance, a molecule of oxygen is made up of two atoms of oxygen bound together. The relative rates at which the molecules of the two gases move is inversely proportional to the square roots of the densities of the two gases.
If two gases (A and B), which have detectable odors, are released simultaneously on one side of a room and the odor of Gas A is noticed one minute before that of Gas B, which of these conclusions can be a likly explanation?
Gas B has a higher density than Gas A
A certain amount of a substance is in a solid state, but is melted to form a liquid and finally vaporized to form a gas. The solid has a volume of one cubic centimeter, the liquid occupies 0.75 cubic centimeters and the gas expands to 10 cubic meters. Which statement is true?
the liquid is more dense than the gas
the solid is more dense than the gas
the liquid has the highest density of the three forms
The general concept of a solution includes solvents (the host substances) and solutes (the dispersed substance). The abundance of a solution's solute determines its concentration (dilute-concentrated). The amount of solute in a solution can be measured by moles (gram formla weights) and therefore can be described as having a certain molarity. The limit to the concentration of a solution is called its solubility. Different compounds range from insoluble to highly soluble.
prazosin, a nerologiccal medication, was prepared in varying concentrations. A patient was given twice a day treatment of 10-4M dosage. The treatment was ineffective, so the doctor decided to DOUBLE the dosage. This molar concentration is expressed as:
2 x 10-4
A scientist is asked to prepare a solution of Trizma-HCI with a concentration of 0.1576 g/L. If a smaller quantity is desired, a technician can conserve chemicals and maintain the same concentration by mixing:
0.1576 mg/ml
There are specific relationships among force, volume, and temperature. Charles' Law states that the volume of a gas varies directly with the absolute temperature, providing the pressure is constant. Boyles' Law states that the volume varies inversely with the pressure at a constant temperature
refer for next 5 questions
Suppose you had a steel cylinder containing a piston which is resting on a block of ice as shown. The piston could be raised or lowered without allowing any of the air in the cylinder below the piston to escape. To test the hypothesis that the greater the force on the piston (hence the smaller the volume of air), the greater the amount of heat generated, which of the methods would be most useful?
Choose three lower levels, move the piston from its original position to each position and measure the amount of water produced in each case.
If an operating refrigerator is placed in a small insulated room for one hour with its door left open, the room temperature will:
increase
The specific heat of a substance is a measure of the quantity of heat required to raise the tmperature of one gram of the substance one degree Celsius. Consider that the specific heat (calories/(gram xoC)) of water is 1.0 and 0.215 for aluminum. If an aluminum pan filled with cold water is placed on a burner at 450 oF, the:
water heats slower and aluminum cools faster
The simple experiment described in question previous supports the hypothesis that:
the experiment does does not address the hypothesis
potassium (K)
is a metal
metals are good conductors
which pair of elements are most alike in reactivity?
A. elements in columsns ( or families) on the periodic table have similar electronic structure and, therefore, similar chemistry
neutrons
add mass and responsible for differences in istopes of a given element
protons and electrons
are responsible for the chemical behavior of atoms.
the number of neutrons in an isotope with an atomic number of 50 is:
likely to exceed 60
one group of chemical elements referred to as a family has gram atomic weights of approximately 19, 35.5, 79.9 and 126.9. If one of these elements is a solid at room temperature, its gram atomic weight must be:
126.9
When comparing two of the same type of toasters, the one capable of generating the most heat is the one with:
higher voltage and higher resistance.
an electric current can be carried by movement of electrons and:
ions
a difference of one pH unit represents a concentration difference of:
10
a difference of two pH units represents a concentration difference of:
100
a substance with a pH of 7 when dissoved in water is:
neutral salt
which of the following characteristics is not a property of acids?
A. liberates OH- in solution
An astronaut who lands on the moon will:
have the same mass on the moon as on earth
An 8.0 kg car travels at 2.0 m/s. If the driver of a 4.0kg car traveling at 2.0 m/s wants to generate the same momentum, she could:
increase momentum by doubling velocity =4 m/s x 4.0 kg =16 kg * m/s. Alternatively, with the addition of 4 kg, it becomes 8 kg x 2 m/s = 16 kg * m/s
if a metal block is to be raised 10 feet either by hoisting it up directly or by pushing it up a frictionless inclined plane 20 feet long, then:
the amount of work by either method is the same
when an automobile traveling at 60 miles per hour is brought to a rapid stop, the two types of energy most involved are:
kinetic and heat
If a person swings a ball in a circle and the string breaks near the point of attachment:
the ball will travel in a straight line
the motion of the released ball occurs due to:
an absence of centripetal force
if four different people with identical body weights are compared, the person who exerts the least amount of energy is the one who:
sits calmly for one hour
Which of the following processes, which involve both chemical and physical change?
B. an egg is harde-boiled
water is recovered last because
it has the highest boiling point. alcohols and their boingin points increase with increasing molecular weight.
A student has two material samples. One is supposed to be a metal (A), and the other is supposed to be a non-metal (B). The student is to determine which one is the metal. During the course of observation, which is likley to be seen?
-Sample B heated very slowly when heat was applied, but Sample A heated very quickly.
-Sample A cooled rapidly when refrigerated, but Sample B did not
-Samples A and B both sank when placed in water
a student heated 200 ml of water in a 1l tin can. After the water boiled, the student closed the can and allowed it to cool.l The student then observed that it crushed from all sides. The demonstration illustrated that:
