Change In The Identity Of A Substance example essay topic

Step's to the scientific method 1. Observing- observing is the use of the senses to obtain information. Observation often involves making measurements and collecting data. The data may be descriptive or numerical in nature. 2.

Formulating Hypotheses- The hypothesis serves as a basis for making predictions and for carrying out further experiments. Hypotheses are often drafted as "if-then" statements. The "then" part of the hypothesis is a prediction that is the basis for testing by experiment. 3. Testing Hypotheses- Testing hypotheses requires experimentation that provides data to support of refute a hypothesis or theory.

If testing reveals that the predictions were not correct, the generalizations on which the predictions were based must be discarded or modified. One of the most difficult, yet most important aspects of science is rejecting a hypothesis that is not supported by data. 4. Theorizing- when the data from experiments show that the predictions of the hypothesis are successful, scientists typically try to explain the phenomena they are studying by constructing a model. Theories are considered successful if they can predict the results of many new experiments.

Qualitative vs. Quantitative Qualitative- to define the properties in an experiment Quantitative- numbering the amount in experiments d = m / vs. Properties of Matter Extensive- depends on the amount of matter that is present. Intensive- does not depend on the amount of matter that is present. Physical- A characteristic that can be observed or measured without changing the identity of the substance. Chemical- Relates to a substances ability to undergo changes that transform it into different substances. Physical changes- a change in a substance that does not involve a change in the identity of a substance. Ex.

Grinding, cutting, melting, and boiling. Chemical change- a change in which one or more substances are converted into different substances. Solids, Liquids, Gases and Plasma Solids- a state that has definite volume and definite shape. Liquid- a state that has a definite volume but an indefinite shape Gas- a state has neither definite volume nor definite shape Plasma- A high temperature physical state of matter in which atoms lose their electrons. Elements vs. Compounds Element- A pure substance made up of only one kind of atom. Compound- A substance that is made from the atoms of two or more elements.

Non-metals, Metals, Metalloids, and Noble Gases Non-metal- An element that is a poor conductor of heat and electricity. Metals- An element that is a good conductor of heat and electricity. Metalloids- An element that has some characteristics of metals and some characteristics of non-metals. Noble Gases- Elements that are generally un reactive, with low reactivity. SI Units and Prefixes Units Quantity Quantity Symbol Unit Name Unit Abbreviation Length L Meter M Mass M Kilogram Kg Time T Second S Temperature T Kelvin K Amount of Substance N Mole Mol Electric current I Ampere A Luminous Intensity lv Candela CD Prefixes Prefix Unit abbreviation Exponential Factor Meaning Tera T 1012 1 000 000 000 000 Giga G 109 1 000 000 000 Mega M 106 1 000 000 Kilo K 103 1000 Hec to H 102 100 Deka Da 101 10 Deci D 10-1 1/10 Cent i C 10-2 1/100 Milli M 10-3 1/1000 Micro M 10-6 1/1 000 000 Nano N 10-9 1/100 000 000 Pico P 10-12 1/1 000 000 000 000 Fem to F 10-5 1/1 000 000 000 000 000 Atto A 10-18 1/1 000 000 000 000 000 000 Homogeneous vs. Heterogeneous Homogeneous- Some mixtures are uniform in composition; such as salt solutions. Heterogeneous- Mixtures that are not uniform throughout; clay in water.

Pure vs. Mixtures Mixture- A blend of two or more kinds of matter, of which retains its own identity and properties. Pure Substance- It has a fixed composition and differs from a mixture.