How many different elements are involved in the reaction shown above?

C1: Matter and Energy

C3H8 + 5O2 → 3CO2 + 4H2O

How many different elements are involved in the reaction shown above?

TEK 6.5C

11-1


TEK 8.5A8.3B11-2

Which of these best describes one of the subatomic particles that could be found at location X in the model of an atom shown above?

A) It has mass but no charge. B) It has no mass and a positive charge. C) It has a large mass and a negative charge. D) It has no mass and an equal number of positive and negative charges.


TEK 8.5C

11-3

An element has a metallic-gray appearance. It also has the properties of both a metal and a nonmetal. In which section of

the periodic table indicated above would the element most likely be found?


A student observes some sugar as it is heated and burns. The student concludes that a chemical reaction has occurred. Which of the following observations about the burning sugar provides

evidence of a chemical reaction?

TEK 8.5E8.2A11-4

A) Heat is added to the sugar crystals. B) The sugar melts and becomes a liquid. C) The temperature of the sugar increases. D) Gas is produced as the sugar turns black.


TEK 6.6B8.4A

13-02

A balance and a graduated cylinder are used to determine the density of a mineral sample. The sample has a mass of 14.7g and a volume of 2.2cm3. What is the density of the mineral sample?

A) 0.15g/cm3

B) 32g/cm3

C) 13g/cm3

D) 6.7g/cm3


TEK 8.5C

13-05

A researcher wants to experiment with an element that reacts like phosphorus (P) but has a greater atomic mass. Which element should the researcher select for the experiment?

A) Nitrogen (N)B) Sulfur (S)C) Arsenic (As)D) Silicon (Si)


TEK 8.5B8.3B

13-11

An atom of which element is represented by this model?

A) Boron (B) B) Carbon (C)C) Neon (Ne)D) Sodium (Na)


Which of the following best describes an electron?

A) It has no charge and about the same mass as a proton.

B) It has a negative charge and much less mass than a proton.

C) It has a positive charge and much more mass than a neutron.

D) It has a negative charge and about the same mass as a neutron.

TEK 8.5A

13-15


A scientist spilled a few drops of dilute hydrochloric acid (HCl) on a lab table. For safety purposes, the scientist sprinkled some baking soda (NaHCO3) onto the spill. Which observation would provide the best evidence that a chemical reaction occurred?

A) The baking soda and hydrochloric acid combined, and bubbles formed.

B) The baking soda absorbed the hydrochloric acid.C) Some of the baking soda dissolvedinthehydrochloric acid.D) Thehydrochloric acid evaporated, leaving only the baking soda.

TEK 8.5E8.1A

13-18


Which information could a student determine from only the chemical formula of a protein?

A) The color of the proteinB) The number of molecules in each sequence that

makes up a proteinC) Thephysicalarrangement

ofatomsinthestructureoftheproteinD) The number of atoms of each element in the

protein

TEK 8.5d

13-20


A teacher asks a student to write the chemical equation for photosynthesis. The student’s response is shown below.

The equation is not balanced correctly. Which of these is a balanced equation for photosynthesis?

TEK 8.5F

13-23


Hay is made up of organic compounds. What are the main elements in many organic compounds?

A) helium, carbon, sodiumB) sodium, hydrogen, nitrogenC) carbon, hydrogen, oxygenD) radon, oxygen, helium

TEK 7.6A

13-31


When trying to identify an unknown element, a scientist determines what other elements the unknown element reacts with chemically. Which property of the unknown element determines the other elements it reacts with?

A) The total number of neutrons in the unknown elementB) The total number of particles in the nucleus of the

unknown elementC) The number of protons in the nucleus of the

unknownelementD) The number of valence electrons in the unknown

element

TEK 8.5B

13-33


The model of the periodic table shows the locations of four elements.

TEK 8.5C8.3B

13-37

A student is asked to identify an element that is a pale-yellow brittle solid and does not conduct electricity. At which location in this periodic table would the element most likely be found?


An atom has 25 protons, 30 neutrons, and 25 electrons. What is the charge of the atom’s nucleus?

A) +25B) +30C) −25D) −30

TEK 8.5A

13-40


How many atoms of oxygen are in a molecule of glucose (C6H12O6)?

TEK 8.5D8.3B

13-44


The chemical equation shown below represents a reaction that produces fuel for certain cars.

TEK 8.5C

13-48

Which substance represented in this equation is classified as an element?A) CO B) H2OC) CO2

D) H2

C1: Matter and EnergyDuring an investigation, a student combined the two clear, colorless solutions. The student observed that the temperature changed from 25°C to 23°C when the solutions were combined and that a white substance rapidly formed and settled to the bottom of the container. What most likely happened to produce these results?A) One of the original compounds came out of

solution. B) The solutions reacted chemically. C) Some of the water froze into ice crystals. D) Rapid evaporation of water occurred, leaving

a solid.

TEK 8.5E8.2E

13-52


TEK 7.6B

14-06

Many processes occur in the digestive system. Which process is best classified as a physical change?

A) Saliva converting the starch molecules in crackers into simple sugars

B) Digestive enzymes breaking down proteins into smaller fragments

C) Bacteria converting lactose into simple sugars in the intestines

D) Teeth grinding an almond into smaller pieces in the mouth


TEK 8.5E8.2E

14-10

Some students in a chemistry lab conducted an investigation in which they added four different solid substances to separate beakers of water. They stirred the mixtures for one minute and then recorded their observations in the table below.

Which substance most likely caused a new substance to be formed when mixed with water?


TEK 7.5C8.3B

14-14

The flow of energy in some Australian food chains is modeled in the energy pyramid.

Based on the model, which consumers would receive the greatest amount of energy captured by the producers in their food chains?

A) Wedge-tailed eagles B) Chuditch C) Ring-tailed opossumsD) Eucalyptus trees


TEK 8.5B

14-16

A student is studying calcium, a highly reactive element that humans need for strong bones. Which characteristic of calcium is most closely related to its chemical reactivity?

A) The 20 protons in each atom of calciumB) The density of calcium, which is 1.54 g/cm3

C) The atomic mass of calcium, which is 40.078 amuD) The 2 valence electrons in each atom of calcium


TEK 8.5A8.3B

14-19

A model of a beryllium atom is shown.What types of particles are found in the cloud

surrounding the atom’s nucleus?

A) Positively charged particles and negatively charged particles

B) Negatively charged particles onlyC) Neutral particles and positively charged

particlesD) Positively charged particles only


TEK 7.6A

14-21

Based on its chemical formula, which of the following substances is an organic compound?

A) Urea, CH4N2OB) Ammonium Sulfide, (NH4)2s

C) Silane, SiH4

D) Sodium Chloride, NaCl


TEK 6.5C8.3B

14-25

In the chemical reaction shown above, the products are best classified as —

A) two elementsB) one element and one compoundC) two compoundsD) two compounds and one element


TEK 8.5D

14-31

The chemical formula for sodium sulfate is Na2SO4. How many sulfur atoms are in the formula for sodium sulfate?

A) 1B) 2C) 6D) 7


TEK 8.5A

14-33

What is the mass number of a potassium (K) atom that has 20 neutrons?

A) 18B) 19C) 20D) 39


TEK 8.5E8.2E

14-39

A scientist performed four investigations using eight different liquids. In each investigation, the scientist combined two of the liquids under a fume hood and recorded observations in the table below

In which investigation is it least likely that the liquids reacted chemically?


TEK 8.5D

14-44

Serotonin is a chemical substance that acts as a neurotransmitter. It helps relay messages in the human brain. The formula for one

molecule of serotonin is shown below.

C10H12N2O

How many atoms in all are in a molecule of serotonin?


TEK 8.5C8.3B

14-46

A student is studying the ways different elements are similar to one another. Diagrams of atoms from four different elements are shown. Which two atoms are of elements in the same group in the periodic table?

A) Atom 1 and Atom 2B) Atom 1 and Atom 4C) Atom 2 and Atom 3D) Atom 3 and Atom 4


TEK 6.6A8.2E

14-48

Some students conducted a laboratory investigation to learn more about the physical properties of different elements. They observed four samples and recorded their observations in the table.

Based on these observations, which sample is most likely a nonmetal?


TEK 8.5B

14-51

The table lists three characteristics of an atom of an element.

An atom of which element is described by the data in the table?

A) Radon (Rn) B) Cadmium (Cd)C) Rubidium (Rb) D) Astatine (At)

TEK 8.5E

15-9

Coal contains carbon and other elements. Carbon dioxide forms when coal burns in the presence of oxygen. Which of these is the best evidence that a chemical reaction occurs when coal burns?

A) The shape of the coal changes.B) Oxygen is present.C) A new substance is produced.D) Coal is made up of more than one element.


TEK 8.5B

15-11

The atoms of a certain element each contain 11 protons and 1 valence electron. Which statement correctly identifies this element

and describes its chemical reactivity?A) The element is sodium, and it is highly reactive.B) The element is fluorine, and it is not very reactive.C) The element is sodium, and it is not very reactive.D) The element is fluorine, and it is highly reactive.


TEK 6.6B8.2E

15-15

For an investigation a student records data about four unknown

substances. The student then calculates the densities of the

unknown substances and compares them with the table of

densities of known substances shown. Which unknown substance

is most likely carbon?


TEK 8.5A

15-17

An atom of a certain element has 36 protons, 36 electrons, and a mass number of 84. At room temperature this element is a very

stable gas. How many neutrons are in this atom?


TEK 8.5F

15-22

All the following reactions are correctly balanced except—

A) 2C2H2 + 5O2 → 4CO2 + 2H2O B) 4Fe + 3O2 → 2Fe2O3

C) NaHCO3 → Na2CO3 + H2O + CO2 D) 2CH3OH + 3O2 → 2CO2 + 4H2O


TEK 8.5C

15-24

The periodic table is organized into groups and periods of elements. The characteristics of a certain group of elements are listed. Which

of these elements is in this group?

A) Lithium B) Strontium C) Aluminum D) Silicon


TEK 8.5D

15-27

Which of these formulas contain equal numbers of nitrogen atoms?A) Formulas I and IIIB) Formulas I and IVC) Formulas II and IIID) Formulas I, II, and V


TEK 6.6A

15-33

Aluminum, sulfur, and chlorine are elements found on the periodic table. Tests involving these three elements would show that at

normal room temperature —A) sulfur is malleable and aluminum conducts electricityB) chlorine is malleable and conducts electricityC) aluminum is malleable and conducts electricityD) all three elements are malleable and conduct electricity


TEK 8.5D

15-36

The equation represents a chemical reaction that occurs in living cells. How many atoms are represented in the reactants of this

equation?

A) 6 B) 12 C) 24 D) 36


C6H12O6 + 6O2 6CO2 + 6h2O + energy

TEK 8.5B

15-39

A chemist is identifying the elements present in a sample of seawater. What characteristic of an element’s atoms always

determines the element’s identity?A) The number of protonsB) The number of neutronsC) The location of valence electronsD) The number of valence electrons


TEK 8.5A8.3D

15-45

In the early 1900s many scientists thought that an atom consisted of a positive substance with negative charges scattered throughout the

substance. Then Ernest Rutherford completed an experiment that changed the concept of an atom. His discovery led to the

understanding that an atom consists mostly of empty space with —A) protons orbiting a dense nucleus made of electrons and neutronsB) electrons orbiting a dense nucleus made of protons and neutronsC) neutrons and protons orbiting a cloud of electronsD) electrons and protons orbiting a cloud of neutrons


TEK 8.5E8.2A

15-48

For an investigation a student poured a blue solution of CuSO4 into a beaker. The student placed a shiny, silver-colored strip of zinc metal in the solution and observed the changes. The student inferred that a chemical reaction occurred.

What evidence supports this inference?A) A dark solid formed on the zinc metal.B) The zinc metal remained silver-colored and shiny.C) The CuSO4 solution turned blue when the zinc metal was added.D) None of these


TEK 8.5C

15-51

Which two elements on the periodic table are in the same period?

A) Sn and RbB) F and ClC) K and BaD) Se and Te


TEK 8.5D

15-54

In which of these compounds are there twice as many oxygen atoms as hydrogen atoms?

A) H3PO4

B) H2SO4

C) HClO3

D) H2O


Documents

How many different elements are involved in the reaction shown above?