science chemistry

Question 1

what are acids and bases?

Answer 1

• when acids react with bases they neutralise each other
• when they react they make salt and water
• salt that is formed is combination of the positive metal ion from base and the negative non-metal ion from acid

Question 2

what does hydrochloric acid produce?

Answer 2

sodium chloride salts

Question 3

what does citric acid produce?

Answer 3

nitrate salts

Question 4

what does sulfuric acid produce?

Answer 4

sulphate salts

Question 5

what are the first 20 elements in the periodic table?

Answer 5

1. hydrogen
2. helium
3. lithium
4. beryllium
5. boron
6. carbon
7. nitrogen
8. oxygen
9. fluorine
10. neon
11. sodium
12. magnesium
13. aluminium
14. silicon
15. phosphorus
16. sulfur
17. chlorine
18. argon
19. potassium
20. calcium

Question 6

what are some characteristics of an acid?

Answer 6

Taste sour, produce a prickling or burning sensation if come in contact with your skin, contain at least one hydrogen atom and tend to react with many metals

Question 7

what is a ph scale reading for an acid?

Answer 7

0-6

Question 8

what is an acid?

Answer 8

Can be strong or weak. Concentrated acids can burn you and would show lower on the pH scale while weaker acids you can eat and drink and would show more neutral

Question 9

what is a ph scale reading for a base?

Answer 9

8-14

Question 10

what are some characteristics of a base?

Answer 10

Taste bitter, feel slippery and soapy, if it dissolves in water it is alkalis

Question 11

what happens to the universal indicator if it turns red?

Answer 11

acid solution

Question 12

what happens to the universal indicator if it turns blue?

Answer 12

base solution

Question 13

what are 3 common acids?

Answer 13

• hydrochloric acid (HCl) is strong
• citric acid (C6H8O7) is weak
• nitric acid (HNO3) is strong

Question 14

what was daltons atomic theory?

Answer 14

All matter is made of atoms. Atoms are indivisible and indestructible. All atoms of a given element are identical in mass and properties. Compounds are formed by a combination of two different atoms.

Question 15

what was Thompsons atomic theory?

Answer 15

• the discovery of an electron and further investigations into atomic structure
• discovered the isotope and the subatomic particle. This is the plum pudding model

Question 16

what was Rutherfords atomic theory?

Answer 16

• The Rutherford model was used to describe an atom. He overturned Thompsonʼs theory and found an atom has a tiny and heavy nucleus.
• He found major portion of the atom is empty, the centre is called the nucleus and the positively charged particles are found in the nucleus

Question 17

what does the current accepted model of an atom consist of?

Answer 17

• Nucleus consists of protons and neutrons
• Protons are positively charged particles
• Neutrons have no charge
• The mass of an atom is mostly because of the mass of the nucleus
• Electrons (are negatively charged) move around the space around the nucleus
• Overall, atoms are neutral (have no charge) because there is always the same number of positive and negative electrons in any atom

Question 18

what is an isotope?

Answer 18

are atoms of the same element with a different number of neutrons

Question 19

what are radioactive isotopes?

Answer 19

they become unstable when the ratio of neutrons to protons is too high,
they may undergo radioactive decay to become more stable
they are radioactive and unstable

Question 20

what is alpha decay?

Answer 20

Nucleus ejects an alpha particle (contains 2 neutrons and 2 protons, occurs in atom with very heavy nuclei can be stopped by a piece of paper

Question 21

what is beta decay?

Answer 21

Nucleus ejects a beta particle (electron) can be stopped by aluminium foil

Question 22

what is gamma radiation?

Answer 22

High energy electromagnetic rays released from the nucleus can be stopped/penetrated by lead