OCR A

ocr pe gcse revision booklet

Balance all atoms apart from oxygen and hydrogen Add H2O to balance oxygen Add H+ to balance hydrogen Add e- to balance charges

What are microscopes used for? - correct answer Observe and investigate different types of cell and cell structure in a range of eukaryotic organisms. How do light microscopes work? - correct answer Shine light through a sample to view living cells and tissues. How do laser scanning confocal microscopes work? - correct answer Uses laser beams to analyse a sample point by point to ...

Light microscope - correct answer Uses light to magnify, due to wavelength of light it is limited to x1500 magnification and max 200nm resolution Transmisson electron microscope - correct answer Electron microscope which creates a 2D image, specimens are dead, max magnification is over x500,000 and max 0.5nm resolution Scanning electron microscope - correct answer Electron microsc...

1869 - correct answer Formation of the American Women Suffrage Association (AWSA) 1869 - correct answer Formation of the National Women's Suffrage Association (NWSA) 1873 - correct answer Women's Crusade 1873 - correct answer Comstock Laws 1874 - correct answer Formation of the Women's Christian Tem...

Aristotle - correct answer A Greek Philosopher, taught Alexander the Great, started a famous school, studied with Plato Empiricism - correct answer the belief that accurate knowledge can be acquired through observation A posteriori - correct answer knowledge gained through experience What are the four causes? - correct answer material, forma...

Which 2 transition metals do not have a fully filled 4s orbital? - correct answer Chromium and copper What advantage does a fully or half filled shell give a transition metal and why? - correct answer Makes more stable What is the definition of a transition element? - correct answer D-block element which form at least one ion with a partially filled d orbital Which 2 elements i...

Electron repulsion theory (VSEPR) - correct answer Electrons are negative, so they will repel each other. Electrons around the central atom determine the shape. The electrons will try and be as far apart from each other as possible. Linear - correct answer AX2, bond angle 180, eg. CO2. Non-linear - correct answer AX2, bond angle 104.5, eg. H2O Trigonal planer - correct answer ...

Electronegativity - correct answer The attraction of a bonded atom for a pair of electrons in a covalent bond. What affects electronegativity? - correct answer Nuclear charge, atom size, how close the shared pair of electrons are to each nucleus. The shared pair of electrons in the covalent bond may now experience more attraction from one of the bonded atoms than the other. How is electronegativity measured? - correc...

What does abiotic mean? - correct answer Non-living What does biotic mean? - correct answer living What is the definition of tropism? - correct answer Growth response to a stimulus What are some examples of an abiotic stimuli? - correct answer Light, water, gravity What are some examples of biotic stimuli? - correct answer ...

What is a sole trader? - correct answer A single person who owns a business and is unincorporated (doesn't exist in its own right) What are the advantages of being a sole trader? - correct answer Few legal requirements, quick, easy, financial info can be kept private What are the disadvantages of being a sole trader? - correct answer Responsible for its debts (unlimited liability...