Atomic Structure & Periodic Table
Which of these determines the identity of an element?
A. number of electrons
B. number of protons
C. number of energy levels
D. number of neutrons
B. number of protons
What happens during a physical change?
A. New substance form.
B. The identity of a substance is changed.
C. A chemical reaction occurs.
D. A property of a substance changes, but its identity stays the same.
D. A property of a substance changes, but its identity stays the same.
Double Points!!
Which statement correctly describes the law of conservation of matter during a chemical reaction?
A. The total number of atoms of each element is the same before and after the reaction
B. The properties of the reactants are the same as the properties of the products
C. The mass of the reactants is always greater than the mass of the products
D. The total number of molecules remains the same before and after the reaction
A. The total number of atoms of each element is the same before and after the reaction
Which of the following is an abiotic factor in an ecosystem?
A. bacteria
B. air
C. niche
D. grass
B. Air
An organism that performs photosynthesis is called
A. a decomposer
B. a consumer
C. an autotroph
D. a heterotroph
C. an autotroph
How are the elements in the modern periodic table arranged?
A. alphabetical order
B. by atomic mass
C. by date discovery
D. by number of protons
D. by number of protons
A physical change is taking place when
A. a nail rusts.
B. onions are chopped.
C. a piece of apple rots.
D. a piece of paper burns.
B. onions are chopped.
Chemical X has a mass of 50 grams, and chemical Y has a mass of 10 grams. If the two chemicals are mixed and a complete reaction takes place, what is most likely the mass of the product?
A. 40 grams
B. 500 grams
C. 60 grams
D. 5 grams
C. 60 grams
A tick has caused a dog to be diagnosed with Lyme disease. What type of relationship would this suggest exists between the tick and the dog?
A. Commensalism
B. Mutualism
C. Parasitic
D. Predator-prey
C. Parasitic
How much of the energy from one trophic level is transferred to the next?
A. None of the energy is transferred.
B. About 1% of the energy is transferred.
C. About 10% of the energy is transferred.
D. All of the energy is transferred.
C. About 10% of the energy is transferred.
Which of these is not made up of two or more substances that are combined physically?
A. homogeneous mixture
B. compound
C. heterogeneous mixture
D. solution
Double points !!
B. compound
A student places a piece of magnesium metal in a test tube containing acid. The student records four observations during the experiment. Which observation describes a chemical change?
1. The magnesium is bendable.
2. The acid is clear and colorless.
3. Gas bubbles form in the test tube.
4.The magnesium sinks to the bottom of the test tube.
3. Gas bubbles form in the test tube.
Given the chemical formula C6 H12 O6 how many oxygen atoms are present in a single molecule of this substance?
A. 6
B. 12
C. 1
D. 3
A. 6
Which of the following factors could cause a decrease in an animal population due to competition?
A. Increase in food resources
B. Increase in the number of predators
C. Increase in shelter availability
D. Introduction of a new species that uses the same resources
D. Introduction of a new species that uses the same resources
Which organism in the food chain is a second-order consumer?
Grass → Cricket → Frog → Snake
A. snake
B. frog
C. cricket
D. grass
B. frog
Double points!!
Scenario: John has a clear, uniform solution that he believes contains only one type of substance. To confirm, he examines it under a microscope and sees no visible particles. He then evaporates the solution and is left with a white crystalline substance.
Question: What type of substance does John have, and how is it classified?
A. Element: homogeneous mixture
B. Compound; pure substance
C. Mixture; heterogeneous mixture
D. Element: pure substance
B. Compound; pure substance
Which is a clue that a chemical change has occurred? A. A beaker becomes warm when you mix two room-temperature liquids in it.
B. A liquid forms bubbles when it reaches a high temperature.
C. Water changes color when food coloring is added. D. A car door feels hot when touched in summer.
A. A beaker becomes warm when you mix two room-temperature liquids in it.
In the chemical equation 2 H2 (g)+O2 (g)→2 H2O (l), how many molecules of hydrogen gas are represented by the coefficient?
A. 1
B. 2
C. 4
D. 6
B. 2
Which factor is most likely to limit the growth of a plant population in an ecosystem?
A. Abundance of sunlight
B. Absence of predators
C. Availability of water
D. Mild temperatures
C. Availability of water
A food chain is shown: Grass → Rabbit → Hawk. If the rabbit population decreased due to disease, what would be the result?
A. The hawk population will increase.
B. The grass population will increase.
C. The food chain will not be affected.
D. The grass population will decrease.
B. The grass population will increase.
How many protons and neutrons do the following elements contain:
C (atomic number 6, mass number 12.01)
Na (atomic number 11, mass number 22.99)
Al (atomic number 13, mass number 26.98)
C-6 protons and 6 neutrons
Na-11 protons and 12 neutrons
Al-13 protons and 14 neutrons
Sally looks at a burning candle on a table. She confirms that it is a chemical change. Which of the following statement confirms this?
A. The candle grew smaller in size as it burned.
B. The candle gave off light and smoke as it burned.
C. The candle wax changed from a solid to a liquid state.
D. The candle wax flowed from all sides of the burning candle
B. The candle gave off light and smoke as it burned.
Which of the following statements correctly represents the balanced chemical equation N2(g) + 3H2 (g) → 2NH3 (g)?
A. One molecule of nitrogen gas and three molecules of hydrogen gas react to form one molecule of ammonia
B. Two molecules of nitrogen gas and three molecules of hydrogen gas react to form two molecules of ammonia
C. One molecule of nitrogen gas and six molecules of hydrogen gas react to form two molecules of ammonia
D. One molecule of nitrogen gas and three molecules of hydrogen gas react to form two molecules of ammonia
D. One molecule of nitrogen gas and three molecules of hydrogen gas react to form two molecules of ammonia
How can predatory interactions affect an ecosystem?
A. They always increase the number of organisms in the ecosystem
B. They may reduce the number of organisms or eliminate whole populations
C. They have no significant impact on the ecosystem
D. They always create mutually beneficial relationships
B. They may reduce the number of organisms or eliminate whole populations
Double Points!!!
In a food web, energy flows from producers to consumers. What else flows from producers to consumers?
A. Light and sound
B. rock and soil
C. chlorophyll and nitrogen
D. oxygen and carbon
D. oxygen and carbon