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The Scientific Method

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Learning Goal: To understand how the scientific method can be used to search for explanations of nature. The scientific method is a procedure used to search for explanations of nature. The scientific method consists of making observations, formulating hypotheses, designing and carrying out experiments, and repeating this cycle. Observations can be either quantitative or qualitative. Quantitative observations are measurements consisting of both numbers and units, such as the observation that ice melts at . In contrast, qualitative observations are observations that do not rely on numbers or units, such as the observation that water is clear. A hypothesis is a tentative explanation of the observations. The hypothesis is not necessarily …show more content…

4. Compounds are formed when atoms of more than one element combine; a given compound always has the same relative number and kind of atoms. Scientists later discovered isotopes, which showed that the second postulate was not entirely true. Consider two different compounds of carbon and oxygen: carbon dioxide, , and carbon monoxide, . The number of oxygen atoms per carbon atom in is double the number of oxygen atoms per carbon atom in . So we can predict that the mass of oxygen per gram of carbon in is double the mass of oxygen per gram of carbon in . And, in fact, if other carbon-oxygen compounds existed, we could predict small, whole-number ratios for the masses of oxygen per gram of carbon in all of them. This is exactly what John Dalton predicted for compounds using his atomic theory of matter. It came to be known as the law of multiple proportions The periodic table is a list of elements arranged by atomic number olumns in the periodic table are called groups, and the rows are called periods. Notice that the groups are labeled 1 to 18 and the periods are labeled 1 to 7. Groups 1, 2, and 13 to 18 are called the main group elements, groups 3 to 12 are the transition elements, and the bottom two rows are called the lanthanides and actinides, respectively. This table gives properties and alternate names for some of the groups: Group | Name | Properties | 1 | Alkali metals | React to form 1+ ions. | 2 | Alkaline

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