ca 6th grade science

The 6 th period consists of elements that have atomic numbers 58 to 71. They are called Lanthanides. The 7 th period consists of elements that have atomic numbers 90 to 105. They are called Actinides. Both of them are called inner transition elements. Lanthanides an..

Calcium sulphate with half a molecule of water per molecule of the salt (hemi-hydrate) is called plaster of paris (plaster of paris..

If 10 grams of CaCO 3 on heating gave 4.4g of CO 2 and 5.6g of CaO, show that these observations are in agreement with the law of conservation of mas..

Deficiency of vitamin D leads to loss of Ca + + in the urine. Due to this, no Ca + + gets deposited in the bone. The result in deformities in the bones of the legs and ribs. This condition is called rickets and occurs in children. The patient has restricted movement of the ..

Question: Which of the following is not a mixed salt? 1. K.Ca.PO 4 2. Ca(OCl)Cl 3. Na.K.CO 3 4. KCl Answer: ..

The rest of the metals occur in the combined form as compounds such as oxides, carbonates, sulphides, sulphates, silicates, chlorides, nitrates, phosphates etc. Copper and silver are two metals which occur in free as well as combined state as sulphide, oxide or halide ores. Metals at the top of th..

Question: Which of the following is a weak base? 1. NaOH 2. KOH 3. NH 4 OH 4. Ca(OH) 2 Answer: ..

Question: Why are the two non-metals, carbon and hydrogen are important chemical reference points with regard to the method of metal extraction and reactivity towards acids. Answer: The six metals K, Na, Li, Ca, Mg, and Al, which lie above carbon in the activity series, cannot ..

Extracting Metals towards the Top of the Activity Series - Metals such as sodium, magnesium, calcium, aluminium high up in the reactivity series are very reactive and cannot be obtained from their compounds by heating with carbon. This is because these metals have more affinity for oxygen than carb..