Unit A Energy and Matter in Chemical Change : Section 1.0 Flashcards

Question

How does fermentation work?

Answer 1

The lactobacilli creates lactic acid which is a preservative. It prevents the growth of bacteria that causes food to rot

Answer 2

Bacteria found in food that that convert starches and sugars into lactic acid

Answer 3

- Preserves food - Increase vitamin levels - Makes food digestible

Answer 4

Introduces antioxidants and formaldehyde to slow the rotting process

Answer 5

- Copper - Bronze - Iron

Answer 6

It was harder, so it could be used to make tools and weapons, and jewelry.

Answer 7

Copper found in the arctic ocean that is found in pure form.

Answer 8

- Handles - Pots - Staples - Rivets

Answer 9

When they hammered it into shapes it became too brittle and broke easily.

Answer 10

By melting it to strengthen it

Answer 11

The heating of a metal before shaping it

Answer 12

Separating metal by melting it

Answer 13

Things were hard to find in pure substances, BUT with smelting metals found in mixtures could be separated

Answer 14

It was made from earth, fire, water, and air

Answer 15

Democritus

Answer 16

A combination of science and magic

Answer 17

By experimenting with volume and gas he concluded that gasses are made up of tiny particles

Answer 18

The law of Conservation of mass

Answer 19

He measured masses of substances that reacted together and the substances created. He discovered that mass is neither produced nor lost in a chemical reaction

Answer 20

The billiard ball model of Atoms. He imagined they were small spheres that could have different properties and varied in size color and mass Dalton’s Atomic Theory • All matter is made up of small particles called atoms. • Atoms cannot be created, destroyed, or divided into smaller particles. • All atoms of the same element are identical in mass and size, but they are different in mass and size from the atoms of other elements.

Answer 21

The Billiard Ball - All matter is made of small indivisible particles - All atoms of an element are identical in properties such as size and mass - Atoms of different elements have different properties - Atoms of different elements could combine in specific fixed ratios

Answer 22

He added electrons In 1894, English physicist J. J. Thomson (1856–1940) used a new version of the gas discharge tube to obtain direct evidence that cathode rays were actually a stream of negatively charged particles. Thomson’s modified gas discharge tube used charged plates to bend cathode rays around a curved path. He knew that by measuring the radius of their path, he could calculate information about the mass and charge of the particles. The electrons in this model are like raisins in a plum pudding or raisin bun. Thus, Thomson’s theory has been called the “plum-pudding” or “raisin-bun” theory. This model (also called the Thomson atom) could not account for a phenomenon that Thomson himself was studying. Radioactive elements had only recently been isolated in pure form. They appeared to be constantly emitting fast-moving, positively charged particles. These particles are called alpha particles and have about 7200 times the mass of an electron. The Thomson atom contained nothing similar to alpha particles, and gave no clues about how they might be formed.

Answer 23

The electron

Answer 24

He was experimenting with beams of particles produced in a vacuum. And they all turned out to be negative which means they all had something in common: the electrons

Answer 25

J.J. Thomson

Answer 26

The raisin bun model was a positive sphere with electrons embedded within it

Answer 27

He said that the core of the atom was called a nucleus and it was positively charged and negative electrons were floating around the nucleus but not in a specific direction In 1909, New Zealand-born physicist Ernest Rutherford (1871–1937) designed an elegant experiment to probe the structure of atoms. As shown in Figure 1.12 on the next page, Rutherford’s apparatus directed a stream of alpha particles from a shielded sample of radioactive polonium toward a very thin gold foil. Collisions with gold atoms, or parts of gold atoms, in the foil were expected to cause the alpha particles to change direction slightly and hit different parts of a fluorescent screen placed near the foil. Rutherford observed this deflection. He observed something else, as well. A small number of alpha particles bounced back from the gold foil.

Answer 28

Ernest Rutherford A nucleus: a central region that is positively charged, extremely small, and yet contains almost all of the atom’s mass. Such a nucleus would be far too dense to be a cloud or shell of positive charge, as Thomson had suggested. Rather, Rutherford visualized the nucleus as containing tiny, relatively massive particles, each with a single positive charge — protons

Answer 29

Gold foil experiment: He released a radioactive material that fired positively at gold and he assumed the they would pass right through but instead, they were deflected which meant they had a strong positive charge

Answer 30

It had a dense positively charged nucleus and around it was mostly empty space with electrons floating around Hydrogen is the element with the least-massive atoms. Rutherford hypothesized that hydrogen would have the simplest possible atom: one proton and one electron. It seemed logical that helium, the next-lightest element, would have two protons and two electrons. That would make a helium atom twice as massive as a hydrogen atom. According to experimental evidence, however, helium atoms are four times more massive than hydrogen atoms. To explain these results, Rutherford hypothesized that there was a third subatomic particle in the atom. He hypothesized that this particle had the same mass as the proton, but no electrical charge. For this reason, he called the particle a neutron. A helium atom, then, would contain two protons and two neutrons (as well as two electrons), making it four times as massive as a hydrogen atom.

Answer 31

He said that electrons surround the nucleus at different energy levels, therefore, they travel in orbits. According to physical theory, electrons moving around a nucleus should constantly emit energy in the form of light or radio waves. This process would cause the electrons to spiral into the nucleus, and the atom would collapse. Atoms, however, do not collapse. There is also no evidence that their electrons emit energy under normal conditions. In a gas discharge tube, however, gases do emit light, but only when electrical energy is supplied to them. As well, each element emits specific colours of light. These colours are different for each element. The colours of light correspond to specific wavelengths. This means that the colours have different energies. Rutherford’s atomic theory had no explanation for this behaviour.

Answer 32

He discovered that different lights are emitted when electrons are from different energy levels - each element emits specific colours of light. These combinations of different colours are different for each element. The colours of light correspond to specific wavelengths. This means that the colours have different energies. For example, there are missing colours on one element compared to the next as seen when you split the light rays into a rainbow.

Answer 33

Neils Bohr

Answer 34

They had a positively charged nucleus and electrions orbited in specific energy levels Energies could be thought of as electron shells or energy levels. Electrons would be associated with specific energy levels. In addition, electrons could move only from one allowed energy level to another

Answer 35

Electrons are thought of as a cloud of negative charges and occupy the whole space at the same time at different electricity levels

Answer 36

Copper and tin

Answer 37

They smelted copper and tin together and the metal produced was much stronger

Answer 38

They realized that Iron could be found in mineral compounds so they were able to smelt it out. Just like Copper

Answer 39

Anything with mass and volume Can be solid, liquid, or gas

Answer 40

The atomic mass number, also known as mass number, (total amount of neutrons and protons) is listed upper left. The atomic number (amount of protons) is listed lower left. The element symbol is listed to the right.

Unit A Energy and Matter in Chemical Change : Section 1.0 Flashcards

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