chemistry for grade 7

1. First period The first period has two elements - hydrogen and helium. 2. Second and third period The second and third periods are known as short periods. Each consists of eight elements. The second period starts with lithium (Z = 3) and ends with inert gas neon (Z = 10)...

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2 SO 4 .10H 2 O Hexagonal a = b ≠ c α = β = 90°, γ = 120° Graphite, ZnO, CdS Rhombohedral a = b = c α = β = γ ≠ 90° Calcite, quartz, NaNO 3 Triclinic a ≠ b ≠ c α ≠ β ≠ γ ≠ 90° ..

Reaction takes place in acidic medium, so add H+ ions to the side deficient in H+ and balance H and O atoms..

How many grams of pure sulphuric acid is present in 0.05 mole of it? (H=1, S=32, O=1..

All the halogens are colored. The color of different halogens are given below: Halogen Fluorine Chlorine Bromine Iodine Colour Light yellow Greenish yellow Reddish brown Dark violet Explanation: The color of halogens is due to the fact that their molecules absorb radiations from..

When carbon dioxide is passed over red-hot carbon in the form of coke charcoal, etc., the carbon dioxide loses one of its two atoms of oxygen. As a result, carbon dioxide gets reduced and becomes carbon monoxide. At the same time the hot carbon also gets converted to carbon monoxide (Fig.11.12). ..

Solute/Solubility 0 o C 20 o C 60 o C 100 o C Calcium hydroxide 1.19 0.17 0.12 0.08 Calcium sulphate 0.18 0.19 0.20 0.16 Cerium sulphate 17.35 9.16 3.73 - If the solute and solvent are both soluble liquids, like alcohol and water, there is no limit to solubility i..

Three hydrogen atoms mutually share one pair of electrons each with a nitrogen atom to form a molecule of ammonia (Fig. 3.10). Note ..

Thus, chemical equilibrium may be defined as the state in which the measurable properties of the system (such as pressure, density, colour or concentration) do not undergo any further noticeable change under given set of conditions is said to be a state of equilibrium. When a reaction is carried i..