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WorksheetsECISD Middle School Science Exam 2019-2020 (STAAR 2018)
Total questions: 42
Worksheet time: 1hrs 5mins
A chemist made the table below to record some atomic properties of four elements. Based on the information in the table, which conclusion about the chemical reactivity of these elements is valid?
Boron is the most reactive because it has the most protons.
Fluorine is the most reactive because it has 7 electrons in the outer shell.
Silicon is the most reactive because it has an equal number of protons and neutrons.
Gallium is the most reactive because it has many more neutrons than protons.
Which statement about stars is correct?
Star formation begins in a nebula.
White dwarfs become main-sequence stars when they gain mass.
Supergiants are stars that can absorb black holes.
Main-sequence stars are formed by comets.
For a laboratory investigation some students put a strip metal into a beaker of blue solution and then stored the beaker on a shelf overnight. The next morning, the students recorded observations about the metal and the solution in the box below. Based on their observations, can the students correctly conclude that a chemical reaction occurred?
No, because the metal strip was still visible
Yes, because a new material of a different color formed on part of the metal strip
No, because the solution stayed blue
Yes, because the volume of the blue solution stayed the same
Which statement describes the energy changes that occur when water in a tea kettle is heated on a stove that uses natural gas?
F
G
H
J
To fight a bacterial infection, a patient was given an antibiotic to take for 10 days. After the patient finished taking the antibiotics as directed, almost all the bacteria were killed. After another 10 days, the patient was sick again with the same type of infection. What most likely happened?
A few bacteria survived the antibiotics and stopped reproducing.
The patient's high fever inactivated the antibiotic, allowing the surviving bacteria to grow rapidly.
The antibiotic slowed the life cycle of the bacteria.
Some of the bacteria were resistant to the antibiotic, and they reproduced.
A 1,000 kg car comes uniformly to a stop. If the vehicle is accelerating at -1.2 m/s2, which force is closest to the net force acting on the vehicle?
-9,600 N
-1,300 N
-900 N
-94 BN
The beginning of autumn in North America is in September, but the beginning of autumn in South America is in March. The diagram shows the positions of Earth, the moon, and the sun on one day in September and one day in March. Why does autumn start in different months of the year in North America and South America?
Earth's orbit around the sun is not a perfect circle.
North America has a larger landmass than South America.
The moon has a greater pull on South America than on North America.
Earth's axis has a 23.5o tilt.
This drawing shows a human body system. What is the primary function of this body system.
The protection of vital organs from injury.
The chemical breakdown of food into smaller pieces.
The transport of nutrients, water, and oxygen to body cells.
The production of hormones that regulate growth and metabolism.
The table lists some compounds found in foods and their formulas. Based on this information, which of these statements is NOT true.
A molecule of sorbitol contains three oxygen atoms than a molecule of glutamine does.
A molecule of lactose contains twice as many atoms as a molecule of fructose does.
A molecule of fructose contains four more atoms than a molecule of glutamine does.
A molecule of lactose contains twice as many carbons atoms as a molecule of sorbitol does.
An ecosystem that is not sustainable can break down when a natural disaster occurs. This can lead to organisms in the ecosystem either leaving the area or dying off. Increased biodiversity results in a more sustainable ecosystem because -
a greater number of plant species means that there is less barren land
a greater variety of species present allows more organisms to adapt after changes occur
the transition area between two ecosystems is narrow
there are fewer species to be affected by environmental stresses
How many valence electrons are in an atom of each element in Group 15 in the periodic table?
5.0
50.0
0.5
0.005
50.0
The photograph shows mountains of the Andes range in South America. Which statement describes the geologic process that is most likely responsible for the formation of these mountains?
F
G
H
J
A group of scientists studied trees in a pine forest. In the densely forested areas, the trees were within 1 m of each other. The scientists observed that these trees had dead branches near the ground. They measured the height above the ground at which the first living branches were found on different-sized trees in the forest. Then they repeated this procedure on the same kind of trees in an open meadow. This graph summarizes the scientists' data. Which inference is best supported by these data?
Pine trees in a dense forest can grow taller than pine trees in an open meadow.
Pine trees in a dense forest compete for sunlight with the surrounding trees.
Pine trees in a dense forest are part of a less-complex food web that pine trees in an open meadow.
Pine trees in a dense forest have more living branches than pine trees in an open meadow.
The picture shows an aerialist walking on a tightrope and holding a balancing bar. An action-reaction pair of forces exists between -
the aerialist's feet and the rope
the rope and the balancing bar
the two ends of the rope
the aerialist's arms and legs
A student drew atomic models of four elements. Based on these drawings, which element is the least reactive?
Neon, because it has two energy levels with eight electrons in the second level
Chlorine, because it has three energy levels with seven electrons in the third level
Gallium, because it has four energy levels with three electrons in the fourth level
Tin, because it has five energy levels with four electrons in the fifth level
Which statement correctly describes the location and charge of the electrons in an atom?
The electrons are inside the nucleus and have no charge.
The electrons are outside the nucleus and have no charge.
The electrons are inside the nucleus and have a negative charge.
The electrons are outside the nucleus and have a negative charge.
Lions and cheetahs prey on wildebeests that graze in the grasslands of the African savanna. What likely effect would increased rainfall over several rainy seasons have on the populations of wildebeests, lions, and cheetahs?
All three populations would increase.
The wildebeest population would decrease, and the lion and cheetah population would increase.
The wildebeest population would increase, and the lion and cheetah population would decrease.
All three populations would decrease.
Which statement accurately describes the atoms of a specific element?
An indium, In, atom contains 115 protons inside the nucleus and 49 neutrons outside the nucleus.
A scandium, Sc, atom contains 45 electrons outside the nucleus and 21 neutrons inside the nucleus.
An aluminum, Al, atom contains 27 electrons and 27 protons inside the nucleus.
A zinc, Zn, atom contains 30 protons inside the nucleus and 30 electrons outside the nucleus.
A student notices that the moon is full one evening. Which sequence of moon phases will the student observe over the next eight days?
Full, waning gibbous, third quarter
Full, waning gibbous, first quarter, waning crescent
Full, new, waning gibbous
Full, waxing gibbous, new, waning crescent
Which statement does NOT correctly compare silicon with another element?
Silicon is better conductor of electricity than sulfur.
Silicon conducts electricity as well as copper does.
Silicon is a solid at room temperature, but argon is a gas.
Silicon is less malleable than silver.
A marble is given potential energy by being placed at Location W. When the marble is released, it rolls down the track. At which location does the marble have maximum kinetic energy?
Location W
Location X
Location Y
Location Z
Which chemical reaction involves the fewest oxygen atoms?
F
G
H
J
A student models convection currents in a laboratory activity. How are the convection currents in the student's model different from the convection currents in Earth's atmosphere and oceans?
The warm air in Earth's atmosphere and the warm water in Earth's oceans sink instead of rise.
The heat source for Earth's atmosphere and oceans is the sun, which heats from above instead of below.
Convection cells in Earth's atmosphere and oceans flow in the same direction instead of opposite directions.
Cold air in Earth's atmosphere and cold water in Earth's oceans are less dense than warm air and warm water instead of being more dense.
Students in a science class in Marfa, Texas, made a poster with a diagram to represent a seasonal change in the Northern Hemisphere. Which statement best describes conditions for Earth at Position 1 in the diagram?
There are an equal number of hours of daylight and nighttime in the Northern Hemisphere, and the North Pole is tilted away from the sun.
The Northern Hemisphere has the fewest hours of daylight, and Earth's axis does not tilt at this position.
There are an equal number of hours of daylight and nighttime in the Northern Hemisphere because Earth's axis is not tilted in this position.
The Northern Hemisphere has the fewest hours of daylight, and the North Pole is tilted away from the sun.
Two forces are applied to a 17 kg box, as shown. The box is on a smooth surface. Which statement best describes the acceleration of the box?
The box accelerates at 1.0 m/s2 to the right because the net force is 17 N to the right.
The box accelerates at 1.9 m/s2 to the right because the greater force is to the right.
The box accelerates at 3.0 m/s2 because the combined forces cause the box to accelerate.
The box does not accelerate, because neither force is large enough to move the box.
Four boxes are sliding with constant speed before each box experiences an unbalanced force of 8 N. Which box would experience the greatest acceleration when the unbalanced force is applied.
The box with a mass of 2 kg.
The box with a mass of 4 kg.
The box with a mass of 6 kg.
The box with a mass of 8 kg.
A mid-ocean ridge is located at the boundary of two tectonic plates. Which diagram correctly models the relative plate motion on each side of a mid-ocean ridge?
A
B
C
D
As part of an investigation, students combined substances in a beaker to observe chemical reactions. They performed two procedures. They measured the mass of each substance before and after each reaction. The table shows their observations. Assuming the students did not make any careless errors, what likely explains these changes in mass?
F
G
H
J
The house sparrow was first introduced to New York in 1851. It is now distributed across most of North America. As the species expanded its range, it began to live in environments that were different from its original habitat. the birds now vary in size, depending on their geographic location. The map shows the distribution of house sparrows by size. What is the most likely explanation for the body-size distribution of house sparrows shown on the map?
Cold temperatures in the North favored the survival of populations of larger sparrows over populations of smaller sparrows.
High elevations int he West provided a survival advantage for populations of larger sparrows over populations of smaller sparrows.
Warm temperatures in the South allowed populations of larger sparrows to survive over populations of smaller sparrows.
Coastal environments in the East tended to give a survival advantage to populations of larger sparrows over populations of smaller sparrows.
A student shows a model of Earth and the moon to a class. Which picture shows how the moon appears from Earth when it is in the position shown in this model?
F
G
H
J
Four students were asked to complete a table for a science assignment. Each student selected one chemical element for each of four groups in the periodic table and then classified each element as a metal, nonmetal, or a metalloid. Which table was completed correctly?
A
B
C
D
A block is pulled 0.90 m to the right in 2.5 s. What is the block's average speed to the nearest hundredth of a m/s?
3.60
36.0
0.361
0.36
This topographic map represents the elevation of an area 100 years ago. At that time the highest point had an elevation of 214 m. The highest point has since eroded a total of 7 m. Which profile most likely represents the landscape today?
A
B
C
D
Some areas of an ocean are known as dead zones. These zones form when excess organic material decomposes. This increased decomposition uses up the oxygen from the water. Which human activity is most affected by the increasing number of dead zones in the ocean?
Offshore oil drilling, because water in dead zones is toxic
Commercial fishing, because fish cannot survive without oxygen
Commercial shipping, because dead zones change the course of ocean currents
Sand mining, because oxygen is not available to form the sands on ocean beaches
Most stars in the universe fit into one of the four areas on this Hertzsprung-Russell diagram. Which area of the diagram represents the white dwarfs?
Area M
Area X
Area P
Area Z
Both the esophagus and the small intestine are involved in the digestion of food. The esophagus squeezes food into the stomach by wave-like muscle contractions. Peptidase enzymes in the small intestine break food molecules into smaller molecules. Which statement best describes changes to food during digestion?
The muscle contractions result in physical changes, while the action of the peptidase results in chemical changes.
The muscle contractions and the action of the peptidase both result only in physical changes.
The muscle contractions result in chemical changes, while the action of the peptidase results in physical changes.
The muscle contractions and the action of the peptidase both result only in chemical changes.
A physics teacher performed a demonstration for a science class by pulling a crate across the floor and measuring the force with a spring scale. While she pulled, a student measured the acceleration of the crate with a handheld electronic device. The results of three trials are shown below. The teacher asked the class to calculate the acceleration of the crate based on the crate’s mass and the force she applied. What conclusion can be made about the difference between the calculated acceleration and the actual acceleration that occurred in the trials?
Another force in the direction of the motion produced a lower acceleration than calculated.
An opposing force caused by friction produced a lower acceleration than calculated.
Another force in the direction of the motion produced a higher acceleration than calculated.
An opposing force caused by friction produced a higher acceleration than calculated.
Wheat was one of the first plant crops that humans domesticated. In the process of domestication, the wild form of wheat was eventually changed into a form more suited to human agricultural practice. Early farmers most likely used seeds only from wheat plants with —
larger grains that could produce more food per plant
taller stems that could block sunlight from weeds growing at ground level
larger flowers that could be sold for additional income
thinner stems that could endure heavy winds
An energy pyramid is shown. Which sentence best describes how energy flows through this pyramid?
Energy is transferred down each level of the energy pyramid.
The energy lost at each level is consumed by organisms in the top level.
Energy is transferred from organisms in one level to those in the level above.
The organisms at the bottom level provide energy directly to organisms in all the other levels.
Students slid a small wood block along a flat tabletop for a distance of 1.6 m. The data show the motion of the block of wood. Which graph displays the motion of the wood block?
F
G
H
J
What keeps planets in the solar system from moving in straight lines through the galaxy?
light energy
gravity
inertia
potential energy
Whitetip reef sharks spend most of the day lying on the ocean floor. While remaining still, these sharks pump water across their gills. The movement of water across their gills is necessary for —
staying cool
accessing food
obtaining oxygen
avoiding predators
