Chemistry can feel overwhelming, but it's really just about understanding... Show more
Chemistry584 views·Updated May 20, 2026·2 pagesAQA Chemistry Paper 1 Higher Level Combined
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arrianne@arr1
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Quantitative Chemistry
Ever wondered why recipes need exact measurements? Chemical reactions work the same way - you need the right amounts of everything.
The conservation of mass is your best friend here. Simply put, atoms don't disappear during reactions, so the mass of your starting materials (reactants) always equals the mass of what you end up with (products). This is why symbol equations must balance - you can't magically create or destroy atoms.
Here's where it gets interesting: the limiting reactant is like the ingredient that runs out first when you're cooking. It determines how much product you can make. The excess reactant is what's left over. For example, if you're making magnesium oxide from 4.8g of magnesium and plenty of oxygen, the magnesium limits you to making just 8g of product.
Concentration measures how much stuff is dissolved in a solution. Think of it like how strong your squash is - more powder in the same amount of water means higher concentration. Remember: 1000cm³ = 1dm³ = 1 litre.
Quick Tip: The mole (6.02 × 10²³ particles) is just chemistry's way of counting huge numbers of atoms - like saying "a dozen" but much, much bigger!
2
of 2
Atomic Structure and the Periodic Table
Everything around you is made of atoms - they're literally the smallest pieces of elements that can exist. It's like LEGO blocks, but for the entire universe.
The periodic table is your roadmap to all elements. When elements team up through chemical reactions, they form compounds (like water from hydrogen and oxygen). Mixtures are different - they're just things mixed together without any chemical bonding, so you can separate them using physical methods like filtering or heating.
Inside every atom, you've got three key players: protons (positive charge, in the nucleus), neutrons (no charge, also in the nucleus), and electrons (negative charge, whizzing around the outside). The atomic number tells you how many protons an element has - this never changes for a specific element.
Isotopes are like twins with different weights - same element, same number of protons, but different numbers of neutrons. Carbon-12 and Carbon-13 are both carbon, just with different masses.
Memory Hack: For ionic compound naming, it's simple - metal first, then non-metal with an "-ide" ending. Iron + Oxygen = Iron Oxide!
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Chemistry584 views·Updated May 20, 2026·2 pagesAQA Chemistry Paper 1 Higher Level Combined
A
arrianne@arr1
Chemistry can feel overwhelming, but it's really just about understanding how atoms work and what happens when they interact. This covers two fundamental areas: quantitative chemistry (the maths side of reactions) and atomic structure (what everything is made of).
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Quantitative Chemistry
Ever wondered why recipes need exact measurements? Chemical reactions work the same way - you need the right amounts of everything.
The conservation of mass is your best friend here. Simply put, atoms don't disappear during reactions, so the mass of your starting materials (reactants) always equals the mass of what you end up with (products). This is why symbol equations must balance - you can't magically create or destroy atoms.
Here's where it gets interesting: the limiting reactant is like the ingredient that runs out first when you're cooking. It determines how much product you can make. The excess reactant is what's left over. For example, if you're making magnesium oxide from 4.8g of magnesium and plenty of oxygen, the magnesium limits you to making just 8g of product.
Concentration measures how much stuff is dissolved in a solution. Think of it like how strong your squash is - more powder in the same amount of water means higher concentration. Remember: 1000cm³ = 1dm³ = 1 litre.
Quick Tip: The mole (6.02 × 10²³ particles) is just chemistry's way of counting huge numbers of atoms - like saying "a dozen" but much, much bigger!
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of 2Sign up to see the content. It's free!
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Atomic Structure and the Periodic Table
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Isotopes are like twins with different weights - same element, same number of protons, but different numbers of neutrons. Carbon-12 and Carbon-13 are both carbon, just with different masses.
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