Chemistry

• A solution that has a pH less than 7 is considered an acidic solution.
• A solution that has a pH greater than 7 is considered an alkaline.
• Neutral substances have a pH value close to 7.
• The hydrocarbon methane makes up most of natural gas
• There was no oxygen in the early atmosphere
• 80% of the air is made up of nitrogen
• 20% of the air is made up of oxygen
• Increased levels of carbon dioxide contribute to global warming
• Climate change is caused by increased levels of carbon dioxide
• The increase in the average temperature of the Earth is called global warming
• Carbon dioxide is released into the atmosphere when biofuels are burned
• Biodiversity is likely to fall as a result of global warming
• Helium is a noble gas often used to fill balloons as it is very light
• Alkali metals is group 1 of the periodic table
• Transition metals are strong and can be made into different shapes fairly easily
• Conductors are metals that allow heat and electricity to pass through them
• Alkali metals are in group 1 of the periodic table
• Transition elements are metals
• Argon is a noble gas and belong in group 0
• Halogens are found in group 7 of the periodic table
• Transition elements tend to have higher melting points than alkali metals
• Hydrogen gas is released when group 1 elements react with water
• Noble gases are unreactive
• Noble gases are inert
• Noble gases do not react with other elements
• Monatomic means that the elements are found as single atoms
• Alkali metals react violently with non-metals
• As you go down group 7 their reactivity decreases
• Group 1 metals are very reactive
• When sodium reacts with water it creates sodium hydroxide
• Group 7 elements react strongly with metals to form ionic compounds
• A substance made of only one type of atom is known as an element
• Dalton stated that all matter is made of atoms which are indivisible
• Carbon dioxide is not an element
• Element is the name for a substance containing only one type of atom
• Atoms are too small to see with the naked human eye
• All matter is made up of atoms
• Substances are made up of atoms
• Dalton stated that compounds are combinations of two or more different types of atoms
• There are approximately 100 elements