Ch E, 1-3 Lecture Flashcards

Question

How does gaseous matter pack, and does it have a fixed volume and shape?

Answer 1

-Gaseous matter have a lot of space between them. They are free to move relative to one another. This makes gasses compressible.

Answer 2

It is made up of only one component, and its composition is invariant(never changing).

Answer 3

1. Elements 2. Compounds This categorization depends on whether or not they can be broken down(or decomposed) into simpler substances.

Answer 4

It is a substance composed of two or more components in proportions that can vary from one sample to another.

Answer 5

It's a substance that cannot be chemically broken down into simpler substances. -Basic building block of matter -Composed of single type of atom, like helium Most elements are chemically reactive and combine with other elements to form compounds such as water or sugar.

Answer 6

It's a substance composed of two or more elements in fixed definite proportions

Answer 7

-Heterogeneous mixtures -Homogeneous mixtures This categorization of mixtures depends on how uniformly the substances within them mix.

Answer 8

It's one in which the composition varies from one region of the mixture to another. – Made of multiple substances, whose presence can be seen (e.g. a salt and sand mixture) * Portions of a sample of heterogeneous mixture have different composition and properties

Answer 9

It's one made of multiple substances, but it appears to be one substance. * All portions of a sample have the same composition and properties (like sweetened tea). * Homogeneous mixtures have uniform compositions because the atoms or molecules that compose them mix uniformly.

Answer 10

A process for understanding nature by observing nature and its behavior through experimentation Key characteristics: -Observations -Formulation of hypotheses -Experimentation -Formulation of Laws and theories (laws cannot be disproven, theories can be)

Answer 11

-Observations are known as data or the descriptions about the characteristics or behavior of nature. -Observations, verification of observations, and experimentation can lead scientists to formulate a hypothesis

Answer 12

- A hypothesis is a tentative interpretation or explanation of the observations. -A good hypothesis is falsifiable: The results of an experiment may support a hypothesis or prove it wrong, in which case the scientist must modify or discard the hypothesis.

Answer 13

-A well-established hypothesis or set of hypotheses form the basis for a scientific theory. * A theory tries to explain not merely what nature does, but why a natural phenomenon happens. ~Characteristics and behavior of nature ~Examples: * Dalton’s atomic theory * Big Bang theory -Theories are validated by experimental results. ~They can be used to predict future observations. ~They can be tested by experiments. -Theories can never be conclusively proven because some new observation or experiment always has the potential to reveal a flaw.

Answer 14

-A brief statement that summarizes past observations and predicts future ones ~For example, the law of conservation of mass: * In a chemical reaction, matter is neither created nor destroyed. -Allows you to predict future observations *So you can test the law with experiments -Unlike state laws, scientific laws cannot be violated by choice

Answer 15

-Subjective in nature -Ex: color, shape

Answer 16

-Objective in nature -Uses equipment (e.g. glassware, balance, instrumentation) capable of generating empirical data with standardized UNITS. -English system (e.g. inch, feet, etc.) -International System of Units (SI) * Metric system

Answer 17

John Dalton *Daltons atomic theory of matter

Answer 18

-It states that in a chemical reaction, matter is neither created nor destroyed -When a chemical reaction occurs, the total mass of the substances involved in the reaction does not change. -This law is consistent with the idea that matter is composed of small, indestructible particles.

Answer 19

1. Each element is composed of tiny, indestructible particles called atoms. 2. All elements don't have the same mass, but it sometimes have similar properties. 3. Atoms combine in simple, whole-number ratios to form compounds 4. Atoms of one element cannot change into atoms of another element. In a chemical reaction, atoms change only the way that they are bound together with other atoms

Answer 20

All samples of a given compound, regardless of their source or how they were prepared, have the same proportions of their constituent elements. -Sometimes is called the law of constant composition

Answer 21

When two elements (call them A and B) form two different compounds, the masses of element B that combine with 1 g of element A can be expressed as a ratio of small whole numbers. * When an atom of A combines with either one, two, three, or more atoms of B, the following molecular compounds are possible: AB1, AB2, AB3, etc.

Answer 22

-A beam of particles called cathode rays, traveled from the negatively charged electrode(cathode) to the positively charged one(anode). -the particles that compose the cathode ray have the following properties: *They travel in straight lines *They are independent of the composition of the material from which they originate (the cathode). *They carry a negative electrical charge - J.J. Thomson was able to measure the charge-to-mass ratio of the cathode ray particles by deflecting them using electric and magnetic fields, as shown in the figure on the bottom of the next slide.

Answer 23

A: Mass number, Z: Atomic number, X: Chemical symbol