A chemistry experiment is performed to determine the effect of a nonvolatile solute on the boiling point of water. Three trials are performed in which 10 mg, 20 mg, and 30 mg of salt are added to 500 mL of distilled water. Each solution is heated on a hot plate, and the elevated boiling points are recorded. Determine the dependent and independent variables in this question.
A. The independent variable is the amount of salt, and the dependent variable is the temperature at which the water boils.
B. The independent variable is the amount of water, and the dependent variable is the temperature at which the water boils.
C. The independent variable is the temperature at which the water boils, and the dependent variable is the amount of salt.
D. The Independent variable is the amount of salt, and the dependent variable is the amount of water.
In a scientific experiment, the dependent variable is the condition that is being tested and measured. The independent variable is the condition that is being changed or controlled. In this example, the amount of salt is varied, and the boiling point of water is measured. Therefore, the independent variable is the amount of salt, and the dependent variable is the temperature at which the water bolls.
Therefore, the Correct Answer is A.
More Questions on TEAS 7 Science
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Q #1: What is a hypothetical explanation for an occurrence that is based on prior knowledge called?
A. Independent variable
B. Dependent variable
C. Trial
D. Hypothesis
Answer Explanation
A hypothesis is the use of prior knowledge in order to provide a hypothetical explanation for why something may or may not occur. A hypothesis can be proved wrong or right based on the results of the experiment and repeated trials.
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Q #2: What is the name for the physical presentation of an organism's genes?
A. Phenotype
B. Species
C. Phylum
D. Genotype
Answer Explanation
Phenotype is the physical presentation of an organism's genes. In other words, the phenotype is the physical characteristics of the organism. Phenotype is often contrasted with genotype, the genetic makeup of an organism. The genotype of the organism is not visible in its presentation, although some of the characteristics encoded in the genes have to do with physical presentation. A phylum is a group of classes that are closely related. A species is a group of like organisms that are capable of breeding together and producing similar offspring.
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Q #3: 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 #4: When animals eat, insulin is released from the pancreas, stimulating glucose uptake by the liver. When glucose levels drop, the pancreas reduces insulin release. This is an example of which mechanism for maintaining homeostasis?
A. Negative feedback
B. Positive feedback
C. Stress response
D. Parasympathetic regulation
Answer Explanation
Maintaining homeostasis means that conditions are kept stable and relatively constant. Negative feedback is a mechanism used to reverse or minimize changes in a system. In this example, negative feedback is used to keep the body's glucose and insulin levels stable. Positive feedback (B) is a mechanism that Increases changes in a system. A stress response (C) describes the body's reaction to threats or pressures. Parasympathetic regulation (D) refers to activities of the nervous system, including slowing the heart rate and boosting Intestinal activity.
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Q #5: 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 #6: A patient lying flat on their back is in which of the following positions?
A. Prone
B. Supine
C. Lateral
D. Medial
Answer Explanation
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Q #7: 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
Answer Explanation
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
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Q #8: Which of these does NOT match the nitrogenous base to the nucleobase?
A. Purine: Adenine
B. Purine: Thymine
C. Pyrimidine: Uracil
D. Pyrimidine: Cytosine
Answer Explanation
There are two types of nitrogenous bases: purine and pyrimidine bases. Purine bases have two rings in their structure and consist of adenine and guanine. Pyrimidine bases only have one ring in their structure and consist of thymine and cytosine (DNA) and uracil and cytosine (RNA). Therefore, the correct answer is B since thymine is a pyrimidine.
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Q #9: Which of the following statements best defines an organelle?
A. Layer of polysaccharides outside the plasma membrane of cells
B. Abnormal Infectious proteins
C. Specialized structures within a cell
D. Collection of tissues used to serve a specific function
Answer Explanation
Organelles are specialized structures within a cell that serve a specific function. For example, mitochondria supply energy to the cell by generating adenosine triphosphate. Ribosomes are the site for protein synthesis. The nucleus is in charge of all of the activities of the cell.
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Q #10: Which section of the digestive system is responsible for receiving chyme and further digesting it?
A. The large intestine
B. The duodenum
C. The jejunum
D. The gallbladder
Answer Explanation
The duodenum is the first section of the small intestine. It receives partially digested food (also called chyme) from the stomach, further digesting it with the help of enzymes released by the gall bladder. Then, the food enters into the jejunum, then the ileum. The large Intestine's main function is the reabsorption of water into the body to form solid waste. It also allows for the absorption of vitamin K produced by microbes living inside the large intestine.
