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प्रश्न
Calculate the percentage of phosphorous in the fertilizer superphosphate, Ca(H2PO4)2. [Ca = 40, H =1, P =31, O = 16] (Correct to 1 decimal place)
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उत्तर
Molecular mass of fertilizer superphosphate, Ca(H2PO4)2 =234
234 parts by weight of fertilizer contains 62 parts by weight of phosphorous
So, 100 parts will contain = 62 x 100/234 = 26.5‰
संबंधित प्रश्न
Fill in the blank.
Molecular weight of a gas is twice its __________.
Potassium nitrate on strong heating decomposes as under :
2KNO3 → 2KNO2 + O2
Calculate : Weight of oxygen formed when 5.05g of potassium nitrate decomposes completely.
(K = 39, 0 = 16, N = 14)
A metal M, forms a volatile chloride containing 65.5% Chlorine. If the density of the chloride relative to hydrogen is 162.5, find the molecular formula of the chloride. [M = 56, Cl = 35.5]
What is the vapour density of ethylene? (Avogadro's number = 6 x 1023; Atomic weight of C = 12, H = 1; Molar volume = 22.4 litres at STP)
4.5 moles of calcium carbonate are reacted with dilute hydrochloric acid.
- Write the equation for the reaction.
- What is the mass of 4.5 moles of calcium carbonate? (Relative molecular mass of calcium carbonate is 100).
- What is the volume of carbon dioxide liberated at STP?
- What mass of calcium chloride is formed? (Relative molecular mass of calcium chloride is 111).
- How many moles of HCl are used in this reaction?
Complete the following calculations. Show working for complete credit :
If the empirical formula of a compound is CH and it has a vapour density of 13, find the molecular formula of the compound.
Calculate the relative molecular mass of:
(NH4)2 Cr2O7
Which of the following contains maximum number of molecules?
Calculate the mass of nitrogen supplied to soil by 5 kg of urea [CO(NH2)2].
[O = 16; N = 14; C = 12; H = 1]
When heated, potassium permanganate decomposes according to the following equation :
\[\ce{2KMnO4 -> \underset{\text{solid residue}}{K2MnO4 + MnO2} + O2}\]
(a) Some potassium permanganate was heated in the test tube. After collecting one litre of oxygen at room temperature, it was found that the test tube had undergone a loss in mass of 1.32 g. If one litre of hydrogen under the same conditions of temperature and pressure has a mass of 0.0825 g, calculate the relative molecular mass of oxygen.
(b) Given that the molecular mass of potassium permanganate is 158. What volume of oxygen (measured at room temperature) would be obtained by the complete decomposition of 15.8 g of potassium permanganate? (Molar volume at room temperature is 24 litres)
