Physical and Chemical Reactions
Is ice melting a physical or chemical change?
A physical change.
What do acids usually taste like?
Sour.
Which Earth system includes all the air and gasses around the Earth?
Atmosphere.
What is the role of the first line of defence?
To keep pathogens out (chemical or physical barriers)
True or False? A dependent variable is the variable that we measure.
True!
True or False? Atoms are destroyed in a chemical reaction.
False!
What is the pH of pure water?
7.
The hydrosphere includes all _____?
Water (oceans, rivers, lakes, groundwater, glaciers, etc.)
Name two types of pathogens.
Bacteria, viruses, fungi.
What is a hypothesis?
A prediction about the results of your experiment.
Name one clue that a chemical reaction has occurred.
Colour change, gas produced, temperature change, releaes of sound or light, formation of a new solid, disappearance of a solid
What happens when an acid reacts with a base?
They neutralise to form a salt and water.
Plants, animals and all living things are part of which sphere?
Biosphere.
A fever and inflammation are examples of a general response to fighting pathogens that have entered the body from which line of defense?
The second line of defense.
What are the three types of variables?
Independent, dependent and controlled
In a chemical reaction, the substances you start with are called ______ and new substances that are formed are called ______?
Reactants;products
How can you tell if a reaction is exothermic?
The temperature increases, it releases heat into its surroundings
Name at least two spheres involved in a volcanic eruption.
Geosphere, atmospehere or biosphere.
What are the names of the white blood cells in the second line of defense and the third line of defense?
Second line of defense - phagocytes
Third line of defense - B cells
I want to investigate whether the amount of food that I eat affects how tired I feel. What is my independent and dependent variable?
Independent variable - Amount of food eaten
Dependent variable - How tired I feel
What happens to chemical bonds between atoms during a chemical reaction?
They are broken and new ones are formed.
A beaker is cold during a reaction. What does this tell you about the reaction that occurred?
Describe one way the atmosphere and biosphere interact.
- Plants take in CO2 and release oxygen
- Humans cause pollution
- Animals breathe air
Different diseases are caused by different pathogens. Each pathogen have unique markers that the third line of defense must identify and produce the corresponding antibody.
In an investigation where I want to test if sports have an effect on lung capacity, what is a control variable and give an example.
Control variable - a variable that you keep constant to avoid errors.
Examples - type of sport, age range, etc.