AQA AS Level Chemistry Paper 1 EXAM/ Final Exam with 100% Correct answers

1.Describe the nuclear model of an atom. [2] - Nucleus containing of protons and neutrons. - Surrounded by electrons in energy levels. 2.State the relative mass and charges of a proton [2]. Mass: 1 Charge: ...

1.Describe the nuclear model of an atom. [2] - Nucleus containing of protons and neutrons. - Surrounded by electrons in energy levels. 2.State the relative mass and charges of a proton [2]. Mass: 1 Charge: +1 3.State the relative mass and charges of a neutron. [2] Mass: 1 Charge: 0 4.Define atomic number (Z). [1] The number of protons in an atom. 5.State the relative mass and charges of an electron. [2] Mass: 1/1840 Charge: -1 6.Define mass number (A). [1] The number of protons and neutrons combined in an atom 7.Define isotope. [1] Atoms with the same number of protons but a different number of neutrons. 8.Describe the chemical properties of two isotopes of the same element. [2] -Same chemical properties. -As same electron configuration. 9.State the uses of mass spectrometry: [4] - Identify elements - Determine relative molecular mass. - Determine isotopic mass. - Determine relative abundance of isotopes. 10.Why is mass spectrometry done in a vacuum? [1] Prevent positive ions from colliding with molecules in the air. 11.Describe electrospray ionisation: [4] - Sample dissolved in volatile solvent. - Injected through a fine hypodermic needle giving a fine mist/aerosol. - Tip of needle connected to positive terminal of a high voltage. - Each molecule gains a proton as it leaves the needle. 12.Describe acceleration: [2] - The positive ions are attracted to a negatively charged plate and accelerate towards it. - All ions accelerate forward so that they have the same kinetic energy, but reach different velocities due to their varying masses. (lighter → faster) 13.Describe ion drift: [2] - Some of the ions pass through a hole in the negatively charged plate, forming a beam of particles. They travel along the 'flight tube' towards the detector. - As the ions are travelling at different speeds, they drift apart further.