science for 3 grade

Sodium Hydrogen Carbonate, (NaHCO 3 ) - Sodium hydrogen carbonate is also known as sodium bicarbonate or baking soda because it decomposes on heating to generate bubbles of carbon dioxide (leaving pores in cakes or pastries and making them light and fluff..

Sodium Carbonate (Na 2 CO 3 ) - Sodium carbonate exists as anhydrous (Na 2 CO 3 ) and also as hydrated salt. The decahydrated salt (Na 2 CO 3 .10H 2 O) is known as washing soda while the anhydrous salt is called soda ash. It occurs native as Na 2 CO 3 .NaHCO ..

Na - 11; 2, 8, 1Number of the valence shell - 3Therefore, sodium is placed in period 3 of the periodic tab..

It is a highly coiled and narrow region measuring about 3.6m in lengt..

Underground reservoirs of fresh water are called aquifers. They are continuously recharged through infiltration, sewage and evapo transpiration. The total volume of ground water found in the aquifer is estimated to be 42.3 x 10 1 0 m 3..

About 0.48 g of a gas forms 100 cm 3 of vapours at STP. Calculate the gram molecular weight of the g..

Question: The number of shells in the elements of 3 rd period is __________. 1. 1 2. 2 3. 3 4. 0 Answer: 3..

Question: Identify the number of replaceable hydrogen ions (H + ) in the following acids: HCl, CH 3 COOH, H 2 SO 4 , H 3 PO 4 . Answer: HCl = 1 CH 3 COOH = 1 H 2 SO 4 = 2 H 3 PO 4 = 3..

. The mouth of the bladder is guarded by a tight ring of muscle called the sphincter which regulates the opening or closing of the bladder. When the sphincter relaxes, urine is released out through the urethra. Urethra This is a short muscular tube that carries urine at intervals from the urinary b..

Element % by wt At wt Relative No.of Atoms Simple Ratio Fe 72.41 56 72.41/56 = 1.29 1.29/1.29 = 1 x 3 = 3 O 27.59 16 27.59/16 = 1.72 1.72/1.29 = 1.33 x 3 = 4 Therefore simple ratio = Fe 3 O 4 .Empirical formula = Fe 3 O..