Chemistry

Revision work for chemistry Grade-8  First term 2021.  Chose the best. What type of reactions can able to change products back to the their original form? Reversible reactions   Irreversible reactions What is meant by the term Hydration in Chemistry? removing water from a substance   adding water to a substance   adding oxygen to a substance   adding Hydrogen to a substance What is meant by the term Dehydration in Chemistry? adding Water to a substance   removing water from a substance   adding oxygen to a substance   adding Nitrogen to a substance Which is the correct symbol to show a reversible reaction? =   →   ⇌   > What is the color and shape of Hydrated Copper Sulfate ? White powder   blue powder   blue crystals   white crystals What is the color and structure of anhydrous copper sulfate? white powder   black crystlas   blue crystals   red powder Dehydration is a .....

Revision work for chemistry  Grade-7 first term. 1.     In 1869 the problem was so lv ed by a Russian chemist ca ll ed ------------------ . Dmitri Mendeleev 2.     There a re ------------------------------ groups in the Pe r iod i c Tab l e. 8 3.     Pe ri ods are t he ------------------  t he Periodic T ab l e. rows across 4.     Group s 1 and 2 are all ------------------ . metals 5.     S il ic o n and g e rmanium are c a l l ed -----------------. Semi metals 6.     -------------- , are unusual metals. They have low melting points and are very soft. alkali metals 7.     The alkali metals get more reactive going ----------- the group. Down 8.     Compounds formed by Group 1 metals are usually --------------- solids . white 9.     T he transition metals a re ' -------------- ' metals. Typical 10. I ron, cobalt and n...