What are the covalent compounds? why are they different from ionic compounds? List their three characteristic properties.
When ethanol reacts with ethanoic acid in the presence of conc. H2SO4, a substance with fruity smell is produced. Answer the following:
i) State the class of compounds to which the fruity smelling compounds belong. Write the chemical equation for the reaction and write the chemical name of the product formed.
ii) State the role of conc. H2SO4 in the reaction.
calcium is an element with atomic number20. Stating reason, answer each of the following questions:
i) Is calcium a metal or a non-metal?
ii) Will its atomic radius be larger or smaller than that of potassium with atomic number 19?
iii) Write the formula of its oxide.
An element 'M' with electronic configuration (2,8,2) combines separately with (NO3)-, (SO4)2-, and (PO4)3- radicals. Write the formula of the three compounds so formed. To which group and period of the Modern Periodic Table do the element 'M' belong? Will 'M' form covalent or ionic compounds ? Give a reason to justify your answer.
i) In which direction, towards the screen or away from the screen, does he move the lens?
ii) What happens to the size of the image? Does it decrease or increase?
iii) What happens to the image on the screen when he moves the object very close to the lens?
List two natural ecosystem.
Following are the two natural ecosystem:
1. Terrestrial ecosystem
2. Aquatic ecosystem