Which of the following answers shows CH4 +2O2=CO2 +H2O as balanced?
A. CH4 + 2O2 = 2CO2 + 2H2O
B. 2CH4 + 4O2 = 2CO2 + H2O
C. 2CH4 + O2 = 2CO2 + H2O
D. CH4 + 2O2 = CO2 + 2H2O
For the formula CH4 + 2O2 = CO2 + H2O to be balanced there must be an equal number of molecules on both the reactant and product sides. In this case, for the formula to be balanced, a coefficient of a 2 needs to be placed in front of the O2 and the H2O molecules. This would make both the reactant and product sides have one carbon, four hydrogens, and four oxygens
Therefore, the Correct Answer is D.
More Questions on TEAS 7 Science
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Q #1: A group of researchers have conducted a study examining the impact of a new medication on blood pressure. What is the purpose of submitting the study for publication in a peer-reviewed journal?
A. Other scientists can validate or disprove the findings.
B. Publication in a peer-reviewed journal will guarantee acceptance of the study's conclusions.
C. Publication in a peer-reviewed journal is unnecessary for this type of study.
D. Publication in a peer-reviewed journal will lead to the manipulation of the study's results.
Answer Explanation
Other scientists can validate or disprove the findings.
The purpose of submitting a study for publication in a peer-reviewed journal is to have the study’s methodology, results, and conclusions evaluated by other experts in the field.
This process helps to ensure the quality and validity of the research. Choice B.
Publication in a peer-reviewed journal will guarantee acceptance of the study’s conclusions is incorrect because publication in a peer-reviewed journal does not guarantee acceptance of the study’s conclusions.
The study’s findings may still be subject to debate and further research. Choice C.
Publication in a peer-reviewed journal is unnecessary for this type of study is incorrect because publication in a peer-reviewed journal is an important step in the scientific process for all types of studies.
Choice D.
Publication in a peer-reviewed journal will lead to the manipulation of the study’s results is incorrect because the peer-review process is designed to prevent manipulation of results by ensuring that the study meets rigorous standards for quality and validity.
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Q #2: Which of the following is a carbohydrate?
A. Cellulose
B. Hemoglobin
C. Estrogen
D. ATP
Answer Explanation
Cellulose is a complex carbohydrate that composes the better part of the cell wall.
Hemoglobin is a protein and is found in red blood cells. Adenosine triphosphate (ATP) is a compound used by living organisms to store and use energy. Estrogen is a steroid hormone that stimulates the development of female sex characteristics.
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Q #3: What is most likely the pH of a solution containing many hydroxide ions (OH-) and few hydrogen ions(H+)
A. 2
B. 6
C. 7
D. 9
Answer Explanation
A solution that contains more hydroxide ions than hydrogen ions is a base, and bases have a pH greater than 7, so the only possible answer is choice D. 9.
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Q #4: How many tissue layers does the uterus have?
A. One
B. Two
C. Three
D. Four
Answer Explanation
The uterus has three layers. The inner layer is called the endometrium. The middle layer is called the myometrium. The outer layer of the uterus is called the serosa or perimetrium.
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Q #5: Which of the following anatomical terms is NOT part of the knee?
A. Medial collateral ligament
B. Patella
C. Lateral malleolus
D. Lateral meniscus
Answer Explanation
The term "lateral malleolus" refers to the bony prominence on the outer side of the ankle.
It is part of the ankle joint, not the knee joint. The other options, such as the medial collateral ligament, patella, and lateral meniscus, are all associated with the knee joint.
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Q #6: Which of the following molecules exhibits ionic bonding?
A. NaCl
B. CO2
C. C6H12O6
D. H2O
Answer Explanation
Sodium chloride exhibits lonic bonding due to the attraction between Na+ ions and Cl- ions.
Typically, elements on the opposite sides of the periodic table (a metal and a nonmetal) form ionic bonds. Carbon dioxide, water, and glucose exhibit covalent bonding. Typically, elements on the same side of the periodic table (two or more nonmetals) form covalent bonds.
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Q #7: Which of the following are examples of homeostatic mechanisms?
A. Increasing heart rate when blood pressure is low, Consuming excess calories to gain weight
B. Lifting weights to increase muscle mass
C. Shivering when the body temperature falls
D. Shivering when the body temperature falls, Secreting insulin to decrease blood sugar concentration, Increasing heart rate when blood pressure is low
Answer Explanation
Homeostatic mechanisms are involuntary actions by organs, glands, tissues and cells to maintain balance within the body. For example, if a person becomes dehydrated, the kidneys will retain fluid by decreasing urine output.
Consuming excess calories and lifting weights are not involuntary actions, nor do they maintain the body in its baseline state. Rather, they are actions specifically taken to move the body away from its baseline.
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Q #8: Which of the following conclusions is supported by the data from this survey?
A. Dally screen usage in the United States decreases with age
B. Daily screen usage in the United States, increases with age.
C. In the United States, most people use screens more than 3 but less than13 hours a day
D. In the United States, people over 75 generally don't use screens.
Answer Explanation
The percentage of respondents that indicated average screen usage between 4-12 hours per day is (628 +650+389) ÷ 2, 307 ≈ 0.723 or 72.3% This is indeed a significant majority of the responses and would be a reasonable conclusion. The highest screen usage is in the middle two groups with both the younger and older groups indicating less screen usage, so the daily usage neither increases nor decreases with age. While the oldest group shows the least usage per day, the survey data indicates that some of the Individuals over 75 do indeed use screens.
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Q #9: There are three Insects that are being compared under a microscope. As a scientist, you decide that measuring them would be an important part of recording their data. Which unit of measurement would best for this situation?
A. Centimeters
B. Meters
C. Micrometers
D. Kilometers
Answer Explanation
The best use of the International System of Units (SI) for this situation would be the use of the micrometer as it is the smallest unit of measurement provided and the scientist is using a microscope to view the insects.
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Q #10: Which of the following is exchanged between two or more atoms that undergo ionic bonding?
A. Neutrons
B. Transitory electrons
C. Valence electrons
D. Electrical charges
Answer Explanation
An ionic bond forms when one atom donates an electron from its outer shell, called a valence electron, to another atom to form two oppositely charged atoms.
