2) write atomic number,symbol and name of the element from 1 to 20
3) name the reactant in respiration?
4) write the reaction of photosynthesis and respiration?
5) name the salts present in hard water?
6)write a chemical equation for combustion of fuel?
7) explain by writing a word equation respiration is a chemical change
8)bubbles are seen on adding lemon juice to baking soda explain with word equation?
Answers
Answer:
2 .
ELEMENT ATOMIC NUMBER SYMBOL
Hydrogen 1 H
Helium 2 He
Lithium 3 Li
Beryllium 4 Be
Boron 5 B
Carbon 6 C
Nitrogen 7 N
Oxygen 8 O
Fluorine 9 F
Neon 10 Ne
Sodium 11 Na
Magnesium 12 Mg
Aluminium 13 Al
Silicon 14 Si
Phosphorus 15 P
Sulfur 16 S
Chlorine 17 Cl
Argon 18 Ar
Potassium 19 K
Calcium 20 Ca
3.
The reactants of cellular respiration are glucose (sugar) and oxygen, these are taken in by animals and humans to produce energy. The cells found in both plants and animals need to produce energy.
4.
Photosynthesis involves the use of energy from sunlight, water and carbon dioxide to produce glucose and oxygen.
5.
Hard water, water that contains salts of calcium and magnesium principally as bicarbonates, chlorides, and sulfates. Ferrous iron may also be present; oxidized to the ferric form, it appears as a reddish brown stain on washed fabrics and enameled surfaces.
6.
C2H5OH(l) + 3 O2(g) → 2 CO2(g) + 3 H2O(l) ΔH
7.
Respiration is a chemical change - During cellular respiration, glucose reacts with oxygen to form carbon dioxide and water. Word equation is - Glucose + Oxygen --> Carbon dioxide + Water
8.
Bubbles are seen on adding lemon juice to baking soda because lemon juice is citric acid and baking soda is sodium bicarbonate. On adding lemon juice in baking soda, we add acid in the base then neutralization reaction is taking place resulting in the formation of salt, water and brisk effervescence of carbon-dioxide.
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