Chemistry

Relative atomic mass (Ar) The mass of an atom of that element compared with one twelfth of the mass of the carbon-12 isotope. Relative molecular mass (Mr) As As

Give 3 examples of electromagnetic radiation X-rays, TV and RF signals What does wave length vary between? 10 to the power of -14 and 10 to the power of 14 What is the speed of all electromagnetic waves? 3X10 to the power of 8 What is frequency? The number of Read more…

What are the ways in which energy change can occur? Energy changes occur as either heat transfer or work, or a combination of both What happens to the energy of the universe during a chemical or physical process? During any chemical or physical process, the energy of the universe remains Read more…

el boligrafo pen la calcudora calculator la carpeta folder la computadora computer el cuaderno notebook el diccionario dictionary el lapiz/los lápices pencil/pencils la mochila backpack mucho(a) a lot of, much muchos(as) a lot of, many ¿Necesitas algo para el colegio/la clase de arte? Do you need anything for school/art class? Read more…

vanderwaals interaction v = -1/r^6(cuu + cuu* +cdisp) multiply by na to get per mole average kinetic energy of translation of a particle Etrans=3/2KT energy of translation per mole Etrans,m = 3/2K×nA×T k×nA=R gas constant Etrans,m=3/2RT dispersion interaction v=-3/2 polarizability vol1 x vol2 × (ionization potential 1 ×potential 2/I1 +I2) Read more…

Is color a physical or chemical property? physical Is texture a physical or chemical property? physical Is mass a physical or chemical property? physical Is clarity a physical or chemical property? physical Is volume a physical or chemical property? physical Is density a physical or chemical property? physical Are melting Read more…

Enthalpy change of formation 1. Standard enthalpy change when 2. one mole of the compound is formed 3. from its elements under 4. standard conditions and standrard states Standard conditions: 298K and 100kpa Eg: Na (s) + 0.5Cl2 (g) → NaCl (s) Enthalpy of atomisation/ sublimation for solid metal 1. Read more…

Rusting Iron Chemical change Melting Ice Physical change Formation of stalagmites in a cave Physical change Fertilizing a lawn Chemical change What are the five signs or symptoms of a chemical change? Production of an odor, change in color, change in temperature/ production of light, formation of a gas/ bubbles, Read more…

What is the phase change for a liquid in an endothermic process? To gas What substance has more than one liquid form? Helium What is the equation m x s x change in temp, used to measure? The energy required to change the temperature in a phase How to you Read more…

Enthalpy a thermodynamic quantity equivalent to the total heat content of a system. H=U+PV Molar Heat Capacity The amount of (heat) energy necessary to raise the temperature of one mole of a substance by 1K Internal Pressure (πT) a measure of how the internal energy of a system changes when Read more…

Ideal Gas Law pV = nRT pVm = RT pV = NKbT Boyle’s Law p ∝ 1/V Charles’ Law p∝T Change in momentum per collision 2m (x) Collision volume A(x)∆t Number of molecules colliding with a wall in a time ∆t [A(x)∆t*n*Na] / 2V – where A is the area Read more…

System The part of the universe being studied Surroundings Everything outside the system Universe Everything that exists and consists of both the system and the surrounding Properties Values that doesn’t depends on time, just a value at that instant. Extensive Property Depends upon the amount of material present. Intensive Property Read more…

What are nucleons and where are they found? Protons and neutrons, found in the nucleus What is the relative charge and mass of a proton, electron and neutron? Proton -> +1 (charge), 1 (mass) Electron -> -1 (charge), 1/1840 (mass) Neutron -> 0 (charge), 1 (mass) How are protons and Read more…

Chemistry the study of the composition, structure, and properties of matter, the processes that matter undergoes, and the energy changes that accompany these processes Organic Chemistry the study of most carbon-containing compounds Inorganic Chemistry the study of non-organic substances, many of which have organic fragments bonded to metals (organometallics) Physical Read more…

What are the effects of Intermolecular forces on real gases and the conditions under which these effects become most evident? Molecules in real gases do not completely obey the ideal gas laws because the molecules are subjected to intermolecular forces known as ATTRACTIONS and REPULSIONS. These effects are typically seen Read more…

chemistry study of the composition, structure, and properties of matter, the process that matter undergoes, and the the energy changes that are accompany in these processes organic chemistry study of most carbon containing compounds inorganic chemistry study of non-organic substances, many of which have organic fragments bonded of metals physical Read more…

Exothermic Releases heat Endothermic Absorbs heat How temperature affects rate of reaction – The higher the temperature, the more kinetic energy the particles have so the faster the particles move – So there are more collisions per second (greater frequency of collisions) and more of the particles have sufficient energy Read more…

Approximate change in Eigenenergies ∆Ei = < ψοi | H1| ψοi > = = H1ii Approximate change in Eigenstates φi = ψοi + Σk≠i [ H1ki / (Eoi – Eok)] ψοk

potential energy for interactions between dipole and a charge V= – (q2µ1)/(4πε₀r^2) potential energy for interactions between dipoles V=µ₁µ₂(1-3cos^2θ)/(4πε₀r^3) Interaction energy between polar molecules in materials (Ideally, it is zero if polar molecules are freely rotating. But, can not freely rotate due to interaction between dipoles even in a gas) Read more…

define the word chemical A substance that has a definite composition how does the composition of a pure compound differ from that of a mixture The proportions of elements in a pure substance are fixed defined property how are properties useful in classifying material A property is any characteristic of Read more…