Across: |
1. | the lowest percent concentration in air (by volume) of a gas or a vapour in air capable of producing a flash of fire in presence of an ignition source. |
4. | the lowest temperature at which the material will ignite without the existence of any ignition source. |
5. | specific groups of atoms responsible for the characteristic chemical reactions. |
8. | the total number of protons and neutrons in the atom. |
9. | the range of a concentration levels of vapor of a flammable or combustible material (expressed as percent by volume in air) at which an explosion will occur in a confined area if an ignition source is present. |
10. | the ratio, at a specified temperature, of the oil density to the density of pure water. |
11. | an indirect measure of the evaporation rate of a liquid. |
13. | the lowest temperature at which it vaporizes to form an ignitable mixture in air in presence of an ignition source (spark, flame, etc.); at the flash point, the vapour may cease to burn when the source of ignition is removed. |
15. | name given to crudes with sulphur content less than 0.5%. |
16. | a chemical process in which small molecules (monomers, all alike or different) react to form a very large chainlike or network molecule (polymer). |
17. | a redox reaction, in which crude oil (or petroleum products) combines with oxygen to ideally produce carbon dioxide, water and heat. |
18. | a process that absorbs heat. |
19. | organic substance consisting entirely of hydrogen and carbon. |
20. | temperature below which wax form a cloudy appearance. |
23. | substance capable to decrease, even block, the rate of the chemical reactions; they play a role when transporting chemicals in bulk able to polymerize, e.g. butadiene. |
24. | the minimum temperature at which the application of a test flame to the oil sample surface causes the vapour of the oil to ignite and burn for at least five seconds. |
25. | type of chemical bond in which pairs of electrons are shared between bonded atoms. |
26. | substance not destroyed during the chemical reaction, provide alternative step(s) for the reaction occur with lower activation energy, thus increasing its reaction rate. |
27. | the mass of oil per unit area that will remain on a standard test surface. |
28. | the smallest component of an element having its chemical properties. |
29. | the lowest temperature at which the oil will just flow under standard test conditions. |
31. | compounds that have at least one benzene ring as part of their chemical structure. |
32. | negatively charged species. |