Dear Students and Respected Teachers! These are Tarjama-tul-Quran class 12th up-to-date papers for all Punjab boards. More papers of coming exams will also be added regularly as soon as the exams are conducted. Here are the PDFs of all these…
Dear Students and Respected Teachers! These are Tarjuma-tul-Quran class 11th up-to-date papers for all Punjab boards. More papers of coming exams will also be added regularly as soon as the exams are conducted. Here are the PDFs of all these…
Dear Students and Respected Teachers! These are Tarjuma-tul-Quran-10th up-to-date papers of all Punjab boards. These are 2024 past papers. More papers of coming exams will also be added regularly as soon as the exams are conducted. Here are the PDFs…
Dear Students and Respected Teachers! These are up-to-date papers for Chemistry-10th for all Punjab boards. These include 2018 to 2024 past papers of all nine educational boards of Punjab. These are PDFs of all these past papers in descending annual…
Dear Students and Respected Teachers! These are 9th class up-to-date papers for Chemistry for all Punjab boards. These are six year past papers from 2018 to 2024 for nine educational boards of Punjab. Here are the PDFs of all these…
ANSWER: Molar mass of urea = 14+2+12+16+14+2 = 60 g Mass of N in the molecule = 28 g % of N = Mass of N / Molar Mass ✕ 100 = 28 gmol-1 / 60 gmol-1 ✕ 100 =…
ANSWER: QUALITATIVE ANALYSIS In qualitative analysis, the elements present in a compound are identified. QUANTITATIVE ANALYSIS In quantitative analysis, the relative amount of each element in a compound is determined. (Ref. An Insight Into Objective Chemsitry-11, Ch-01, Q. No. 29)
ANSWER: In mass spectrum, the number of peaks tells about the number of isotopes, while the heights of the peaks represent their natural abundance. Two equally strong peaks in the mass spectrum of bromine indicate that bromine has two isotopes…
ANSWER: Neon has three isotopes Ne–20, Ne–21 & Ne–22, having percentage abundance of 90.92%, 0.26% & 8.82% respectively. When we calculate average of all these isotopic masses in proportion to their natural abundances, a fractional value of 20.18 amu is…
ANSWER: Most of the elements have fractional atomic masses. This is because most elements have isotopes, each with different natural abundance. The atomic mass is actually the average of all the isotopic masses, proportional to their relative abundance. So, their…