Science For Life Exam 2022

identify the forces acting on a motor vehicle in straight line motion on a horizontal surface

Newton's First Law of Motion

inertia, an object will not change its motion unless a force acts on it

Newton's Second Law of Motion

f=ma

Newton's Third Law of Motion

for every action there is an equal and opposite reaction

why do cars have crumple zones?

Purpose: to absorb the force of the crash
Laws of motion: 2nd law - when there is a collision the crumple zone absorbs the force which slows
down the car and there is less force on the passengers.

why do cars have seatbelts?

Purpose: protects people when the car is in motion and avoid unnecessary movement.
Laws of motion: 1st - as our bodies move, the seatbelts push back and prevent them from moving
Forward

why do cars have headrests?

Purpose: protect and reduce the motion of the head and the neck

Laws of motion:
3rd - action is the force of the impact, reaction is stopping the neck from breaking.

1st - head is moving and if the head rest isn’t there to stop the head from moving, the damage will
be more severe like neck snapping or spine breaking

Know that the weight on Earth is differnt to the weight on the Moon and why?

It is becuase the gravitational attraction on the Moon is much less than it is here on Earth

Atomic Number

Number of Protons

Atomic structure

Size - electron < proton < neutron

atomic mass

Number of protons + number of neutrons. You can work out the number of neutrons by subtracting the number of protons from the mass number.

Electron Configuration – Electron shells

2 in the first shell and 8 in the rest (formula: 2n^2)

Periodic table Groups and Periods

Groups/family (vertical columns)

Periods (Horizontal lines)

Periods

the period (row) of the periodic table that an element is in correlates to the number of electron shells it has. For example, carbon is in period 2 and thus has 2 electron shell

Groups

The group (column) indicates how many electrons the element has in its outermost shell
Elements in the same group have similar properties. For example, all the elements in Group 1 are highly reactive metals.

Metals, Non-Metals, and Metalliods

Metals: elements that conduct heat + electricity and are shiny solids that can be made into thin wires and sheets.


Non-metals: elements that do not conduct electricity or heat and usually have a lower boiling and melting point than metals.

Metalloids: elements that have features of both metals and non-metals.

Cations

- Have Positive charge
- Have lost electrons

Anions

- Have a negative charge
- Have gained electrons

Ionic Bonding

To write the formula of a compound, first, calculate the charge of both elements. Then find the symbols for each element and swap the charges.

Naming Ionic compounds

Metal is named first and its name is not changed.
Non-metal is named second and the end of its name is changed from -ine to -ide

Naming Covelant compounds

1. Write the name of the FIRST element
2. write the name of the SECOND element -ide ending
3. Use prefixes to tell the number of atoms of each element

Covelant bonding

A covalent bond consists of the mutual sharing of one or more pairs of electrons between two atoms.

IONIC VS COVELENT STRUCTURE

Combustion ( type of reaction )

Combustion is when oxygen reacts with any other substance. It usually produces heat and carbon dioxide.

Neutralization

is when an acid reacts with a base producing salt and water.
- Sulfuric acid always forms sulfates
- Hydrochloric acids forms chlorides
- Nitric acid forms nitrates
when writing a salt the first name is from the metal and the second is from the acid.

Synthesis

Synthesis reactions occur when two substances
(generally elements) combine and form a compound
Reactant 1 + Reactant 2 → Product
Eg. C + O2 → CO2

Decompostion

Decomposition is when a compound breaks down into elements
1 Reactant → Product + Product
Eg. 2H2O → 2H2 + O2
2HgO → 2Hg + O2

Single displacement

One metal deposits on another. A metal solution reacts to become a pure solid metal.
Eg. Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s)
Fe(s) + CuSO4(aq) → FeSO4(aq) + Cu(s)

A + BC → B + AC
For A to kick out B, A has to be more reactive. If B is more reactive, it keeps its position and stays the same.

Double Replacement

A metal replaces a metal in a compound and a non-metal replaces a non-metal compound
( Ions switch partners )
AB+ CD-> AD + CB

DNA

A molecule containing genetic information is in charge of construction and development.

Basic structure NUCLEOTIDES

- Phospahte group
- Nitrogenous Base
- Pentose Sugar

BASIC CODES -

ADENINE, THYMINE, GUANINE, CYTOSINE

Car in a garage ( Cytosine + Guanine)
Apples in a tree (Adenine + Thymine)

CHROMOSOMES

A structure found inside the nucleus of a cell.
A chromosome is made up of proteins and DNA organized into genes.
Each cell normally contains 23 pairs of chromosomes.

Chromosomes structure

Autosomes

control the inheritance of all an organism's characteristics except the sex-linked ones. Humans have a diploid genome that usually contains 23 pairs of autosomes and one allosome pair (46 chromosomes total).

sex chromosomes

A type of chromosome involved in sex determination. Humans and most other mammals have two sex chromosomes, X and Y. Females have two X chromosomes in their cells, while males have one X and one Y.

SEX DETERMINATION AND PREDICTIONS

A child's biological sex (male or female) is determined by the chromosome that the male parent contributes. Males have XY sex chromosomes while females have XX sex chromosomes; the male can contribute the X or Y chromosome, while the female must contribute one of their X chromosomes.

Gene

The basic unit of heredity is passed from parent to child.

Homozygous

having two identical alleles of a particular gene or genes.

Heterozygous

having two different alleles of a particular gene or genes.

Alleles

An allele is one of two or more versions of a DNA sequence (a single base or a segment of bases) at a given genomic location.

Dominant/recessieve

Relating to or denoting heritable characteristics controlled by genes that are expressed in offspring only when inherited from both parents.

Dominant- An allele of a gene is said to be dominant when it effectively overrules the other (recessive) allele.

Recessive - A recessive gene is a gene that can be masked by a dominant gene.

Genotypes

A person's genotype is their unique sequence of DNA

Phenotypes

Phenotype refers to an individual's observable traits, such as height, eye colour and blood type (Characteristics)

Mitosis

Cell division for growth and repair

meiosis

Cell division for the production of sex cells

Negitaves of genetic technology

Potential Harms to Health. New Allergens in the Food Supply. Antibiotic Resistance. Production of New Toxins. Concentration of Toxic Metals. ...

Potential Environmental Harms. Cross Contamination.
Increased Weediness. Gene Transfer to Wild or Weedy Relatives. ...
Unknown Harms to the Environment.

positives of genetic technology

Genetic technologies are changing the way we produce food, improving crop yield and preventing catastrophic losses from droughts, floods and pests.

Climate change

Climate change refers to long-term shifts in temperatures and weather patterns.

Consequences of global warming

melting ice caps, rising sea levels, extreme weather, drought, increased extinction rates, tropical diseases

Natural greenhouse effect

Heat buildup in the atmosphere due to the presence of 'greenhouse' gases like carbon dioxide, methane, and water vapor.

enhanced greenhouse effect

the increased capacity of the atmosphere to trap thermal energy because of an increase in greenhouse gases due to human activity

Carbon cycle

Describes how carbon moves between the atmosphere, soils, living creatures, the ocean, and human sources.