Is copper an element, a compound, or a mixture? Explain. What is sodium made of? Which alloy of aluminum is used for making magnets? How are the pure metals prepared? In your own words, how would you define chemistry? What are "chemicals" and what do "chemists" do?
1. Distinguish between a deliquescent and a hygroscopic substance. 2. Give one use of hygroscopic substance in the laboratory 3. What is meant by the terms I. Element II. Atomic number.? Define the term chelate. Is wood classified as an element, a compound, or a mixture? Explain. ...
Graphite is a brittle steel black coloured compound that is used in several different industrial inductor processes as well as in the lady for your pencil. To make graphite in the lab we need the flowing material 1) 10- 15 gram of sucrose, 2) 10 mils of 18 molars sulphuric acid, 3) 1...
The bioaccumulation of compounds in algal biomass has also been applied to take up PCBs; the compound was taken up into the cell organelles, as well as attached to the surface of the cell (Jabusch & Swackhamer, 2004). Algae are good accumulators of industrial compounds like organochlorides an...
A layer of interface material such as graphite is then applied to keep the MnO2 from reacting with the metal layer (commonly silver) needed in order to have something to attach a lead to, before the whole assembly is packaged in epoxy and tested prior to shipment. The end product is a ...
Thermally expandable graphites are becoming increasingly popular as intumescent fire retardants for polymeric systems due to their excellent thermal and barrier properties. Therefore, it is important to understand their thermal degradation pathways and monitor products for any that may be toxic or affect ...
an element, and not what an element is and what distinguishes one from another. And it is highly provisional, hostage to your analytical capabilities. How could you be sure that you had an element and not just a compound that no one had yet found a way of splitting into its ingredients?
Mixture or "pure substance" ? In science it is necessary to know exactly what we are talking about, so before we can even begin to consider matter from a chemical point of view, we need to know something about its composition; is the stuff I am looking at a single substance, or is ...
It also revealed good reproducibility with a superior LOD of 37 nM. Complementarily, Sahyar et al. [87] immobilized xanthine oxidase onto a modified electrode of entrapped silver-doped zinc oxide nanoparticles (nano-Ag-ZnO) on a pencil graphite electrode electropolymerized by pyrrole. The ...
If the soot is produced by the pyrolysis of aromatic hydrocarbons instead of the laser ablation of graphite, Soxhlet extraction from the soot (with organic solvents) will be required, followed by chromatographic separation. This illustrates a situation where physical or chemical methods can be ...