WorksheetsFirst Semester
Total questions: 44
Worksheet time: 22mins
The item pictured here is found in each science classroom. How are these devices used?
Used to wash harmful materials out of eyes or off body
Used to clean up after the lab is completed
Used for correct hand washing after experiments
Used only in the event of a laboratory fire
A scientist observes that a chemical reaction rates increase when exposed to high‑energy, small‑wavelength light. What would be an appropriate scientific inference?
Infrared light most probably induces reaction progress
The reaction occurs quickly with orange and yellow light
Radio waves would be a good choice to increase the reaction rate
Ultraviolet light could be used to make a reaction happen faster
How do scientists use observations to form inferences?
They use intuition and feelings
They only record data without interpretation
They guess based on past experiences
They apply reasoning to interpret observations and propose explanations
A scientist's conclusion supports their company's product. What is a potential concern?
The data is likely to be free of error
The scientist may be biased due to a conflict of interest
The results must be correct because they benefit the company
Scientists never have personal beliefs
How can personal bias affect scientific research?
It improves the accuracy of measurements
It may influence data interpretation or the design of experiments
It leads to stronger conclusions
It ensures objectivity
From the graph of mass vs. volume for pennies, estimate the density of the metal in g/cm^3 if a straight line through the points has slope near 7 . Use density = slope (mass/volume).
7 g/cc
21 g/cc
12 g/cc
5.9 g/cc
How many milliliters are in4.5 liters? Use 1 liter = 1000 milliliters.
0.0045 mL
45,000 mL
450 mL
4,500 mL
A metal sample has mass 0.015 kg and displaces 2.00 mL of water. What is its density in g/mL? Use 1000 g = 1 kg.
50 g/mL
7.5 g/mL
.25 g/mL
.005 g/mL
A wave travels at 90.0 km/h. What is the speed in m/s? Use 1 km = 1000 m and 1 hour = 3600 s.
15 m/s
45 m/s
30 m/s
25 m/s
The diagrams show particles in ice and in liquid water. Which explanation best accounts for why ice floats on liquid water?
Ice is less dense because particles form an open lattice
Ice is more dense because particles pack into rigid layers
Liquid water is less dense because particles spread farther apart
Density of ice and water is equal so floating is random
Which statement correctly distinguishes a liquid from a solid at the particle level?
Solid particles move faster than liquid particles
Particles are fixed in place and cannot move
Liquids have definite shape while solids do not
Particles are close together but move past each other
During evaporation of water, what change in particle behavior occurs?
Particles slow down and move closer together at surface
Particles stop moving and are knocked off by others
Particles gain energy and escape from the surface
Particles lose energy and form rigid surface structures
As time increases of this graph, what is happening to the molecules of water?
Gain kinetic energy and move faster
Lose kinetic energy and move close together
Distance between molecules remains constant
Distance between molecules decreases
Which phase change releases heat energy to the surroundings?
Sublimation of solid to gas
Condensation of gas to liquid
Evaporation of liquid to gas
Melting of a solid to liquid
A heating curve shows temperature rising, leveling during a plateau, then rising again. As time increases on this graph, what happens to water molecules overall?
Lose kinetic energy and cluster closer
Gain kinetic energy and move faster
Distance between molecules remains constant
Distance between molecules decreases
Nails are often composed of iron due to iron’s chemical and physical properties. Which of the following is a chemical property of iron?
Iron can be hammered into sheets
Iron is magnetic in bar form
Iron rusts when exposed to oxygen and moisture
Iron has a density of 7.87 g/cm³
A student places sugar in hot tea. The sugar dissolves completely, and the tea tastes sweet. Which best describes the change?
Chemical change, because added heat provided energy
Chemical change, because the sugar’s identity is destroyed
Physical change, because the tea became a new substance
Physical change, because the sugar molecules are present
Which observation best indicates that a chemical change has occurred?
A solid melts into a liquid state
A gas is produced and bubbles form
A substance is broken into pieces
A liquid freezes into a solid
Refer to the two containers in the diagram showing mixtures of particles. One shows evenly distributed particles, while the other shows clumps or clustering. Using evidence from the diagrams, which definition BEST describes these two containers?
Both containers have heterogeneous mixtures
Container A is heterogeneous, B is homogeneous
Container A is homogeneous, B is heterogeneous
Both containers are homogeneous mixtures
Which of the following is an example of a homogeneous mixture?
Soil with leaves and composted materials
Saltwater containing dissolved sodium chloride and water
A salad with lettuce, tomatoes, cucumbers, cheese
A beaker with nails, staples, paperclips of iron
Which conclusion from Rutherford’s gold foil experiment is most accurate?
Protons and neutrons fill space evenly throughout atoms
The nucleus is large, diffuse, and negatively charged
Atoms are mostly empty space with a small, dense, positive nucleus
Electrons orbit in fixed planet-like circular paths
Which conclusion from Rutherford’s gold foil experiment is most accurate?
Protons and neutrons fill space evenly throughout atoms
The nucleus is large, diffuse, and negatively charged
Atoms are mostly empty space with a small, dense, positive nucleus
Electrons orbit in fixed planet-like circular paths
Which statement correctly compares subatomic particles?
Protons are negative and have the largest mass
Neutrons are lighter than electrons and neutral
Electrons and protons have same mass but opposite charge
Protons and neutrons have similar mass; electrons have much less
Two atoms each have 10 protons and 10 electrons. Atom A has 13 neutrons; Atom B has 15 neutrons. What best describes their relationship?
Same element because total particles differ
Ions of same element due to equal neutrons
Different elements because neutrons differ
Isotopes of same element with different neutrons
The table shows subatomic counts. Which statement BEST explains the relationship among the elements?
All different elements due to different neutrons
A and C are isotopes; B is different
A, B, and C are different forms of same element
A and B are isotopes; C is a negatively charged anion
What is the primary role of electrons in an atom?
Define mass of atom
Stored in nucleus to balance charge
Give atom its color
Orbit nucleus and participate in bonding
What determines an element’s position in the periodic table?
Number of protons
Physical state at room conditions
Atomic mass value
Number of neutrons
Which group contains elements least likely to react with others?
Alkali metals
Halogens
Noble gases
Transition metals
Two elements are in the same group. Why do they have similar chemical properties?
Same total electrons
Same number of protons
Same neutrons in common isotope
Same valence electron count
Which element is more electronegative: oxygen (O), sulfur (S), or selenium (Se)?
Sulfur (S)
Selenium (Se)
Oxygen (O)
All have equal electronegativity
Sodium (Na) and chlorine (Cl) are in the same period. Which statement BEST explains which atom has the larger atomic radius?
Chlorine larger: more protons makes it heavier
Sodium larger: outer electrons farther, less effective nuclear pull
Chlorine larger: nonmetal expands outward
Sodium larger: more protons pull electrons inward
Which type of electromagnetic wave has the longest wavelength and lowest frequency?
Gamma rays
Ultraviolet rays
X-rays
Radio waves
In which section of the spectrum would you expect the waves to have the highest frequency and highest energy?
Left side
Right side
All sections have equal energy, only wavelength changes
Center (area around visible light)
Cell phones and radios use specific radio frequencies to transmit information. Why are radio waves suited for this purpose?
Radio waves are shorter in wavelength than gamma rays, making phones safer
Radio waves have long wavelengths that travel far and penetrate obstacles
Radio waves have more energy than visible light or ultraviolet
High-energy radio waves are absorbed by the atmosphere and cannot travel far
In the chemical equation 2H2 + O2 → 2H2O, what do the numbers in front of the molecules represent?
The identifier shows the rate of the reaction
The coefficients show the number of molecules involved
The exponent shows the number of atoms in a molecule
The subscript shows the number of molecules in the reaction
Which of the following is a balanced chemical equation?
2H2 + O2 → 2H2O
Na + Cl2 → NaCl
H2 + O2 → H2O
C + O2 → CO
What does it mean for a chemical reaction to be balanced?
The phase of each item is represented
The same number of each type of atom appears on both sides
The same amount and types of energy are equal on both sides
The products are equal in volume to the reactants
What does the formula H2O represent?
Two hydrogen atoms and two oxygen atoms
Two hydrogen atoms and one oxygen atom
One hydrogen and two oxygen atoms
Two hydrogen molecules and one oxygen atom
Which formula shows a properly written compound made of two aluminum atoms and three oxygen atoms?
AlO
Al2O3
Al3O2
Al2O
Which statement best describes an ionic bond?
Equal sharing of electrons between two nonmetals
Transfer of electrons from a metal to a nonmetal
Weak attraction within a single molecule
Overlap of electron clouds in metallic atoms
What distinguishes a covalent bond from an ionic bond?
Formed between metals and nonmetals
Weaker than hydrogen bonds
Involves a transfer of electrons
Involves the sharing of electrons between atoms
In the diagram of two water molecules, what type of bond is represented by the dotted line between the molecules?
Oxygen bond
Covalent bond
Ionic bond
Hydrogen bond
Water has a high specific heat capacity. Which effect best explains why this property supports life on Earth?
Enables upward movement of water in plant stems
Helps maintain stable temperatures in oceans and on land
Allows organisms to dissolve nutrients for survival
Allows ice to float, insulating aquatic organisms
Why is water often called the universal solvent?
Its ionic bonding dissolves many substances
Its polarity lets it dissolve many substances
Its covalent bonding dissolves only gases
It dissolves all heterogeneous substances
