Elements, compounds & mixtures
What is a substance made from only one type of atom called?
An element
Alkali, Alkali Earth, gases, transition, non-metals
What is the main job of the digestive system?
To break down food and absorb nutrients.
What is the aim of an experiment?
Goal of the experiment / what you set out to achieve
What is the smallest unit of an element that still has the properties of that element?
Atom
Is water (H₂O) an element, compound or mixture?
Compound
Which element has the chemical symbol Na?
Sodium
Which side of the heart pumps blood to the rest of the body?
Left side
A student investigates whether the amount of sunlight affects plant growth. What is the dependent variable?
Plant growth, such as height or number of leaves.
An athlete drinks water containing dissolved salt. Is this a mixture or a compound?
Mixture
What 2 elements chemically bond together to create table salt?
Sodium + chlorine
The atomic number (an elements position on the periodic table) tells us what about the element?
How many protons/electrons it has
Which body system is responsible for taking oxygen into the body?
The respiratory system.
Why should a scientist repeat an experiment several times?
Reliability
What is the process of a liquid changing into a gas called?
Evaporation
What is the difference between a compound and a mixture?
A compound contains elements chemically bonded together. A mixture contains substances physically combined, not chemically bonded to each other.
An element has the symbol C. What is its name, and is it a metal or non-metal?
Carbon; it is a non-metal.
The kidneys are the major organ of which body system?
Excretory system
A student thinks plants grow faster when given more water. What is the hypothesis, independent variable and dependent variable in this experiment?
Hypothesis: Plants given more water will grow faster.
Independent variable: Amount of water.
Dependent variable: Plant growth.
What is the chemical symbol for the element that makes up most of the gas we breathe?
N
Is air an element, compound or mixture? Explain your answer.
Air is a mixture because it contains different gases, including nitrogen, oxygen and carbon dioxide, that are not chemically bonded together.
Which element has 8 protons?
Oxygen
Which two body systems work together to deliver oxygen to your muscles when you exercise? Explain how.
The respiratory system brings oxygen into the lungs, and the circulatory system transports oxygen in the blood to the muscles.
A student tests which sports drink helps a plant grow the tallest. They use different amounts of sports drink but also give each plant different amounts of sunlight. What is wrong with the experiment?
There is more than one independent variable. Different sunlight amounts make it difficult to determine whether the sports drink caused the difference. The sunlight should be kept the same.
A student mixes sand and water. Is this a mixture or a compound? How could they separate the sand from the water?
It is a mixture. They could use filtration to separate the sand from the water.