{"questions":[{"id":"inter-chem11-stoi-01","v":1,"subject":"chemistry-11","chapter":"stoichiometry","seed":true,"difficulty":1,"stem":"The value of Avogadro's number is:","options":["6.022 × 10²³","6.022 × 10⁻²³","3.011 × 10²³","1.66 × 10⁻²⁴"],"answer":0,"explain":{"en":"One mole of any substance contains 6.022 × 10²³ particles (atoms, molecules or ions). 1.66 × 10⁻²⁴ g is one atomic mass unit.","ur":"کسی بھی مادے کے ایک مول میں 6.022 × 10²³ ذرات (ایٹم، مالیکیول یا آئن) ہوتے ہیں۔ 1.66 × 10⁻²⁴ g ایک ایٹمی ماس اکائی ہے۔"},"source":{"kind":"parcha-original"},"status":"sample","exam":"inter"},{"id":"inter-chem11-stoi-02","v":1,"subject":"chemistry-11","chapter":"stoichiometry","difficulty":1,"stem":"How many moles are there in 36 g of water (H₂O, molar mass 18 g/mol)?","options":["0.5","1","2","18"],"answer":2,"explain":{"en":"Moles = mass ÷ molar mass = 36 ÷ 18 = 2 mol.","ur":"مول = ماس ÷ مولر ماس = 36 ÷ 18 = 2 مول۔"},"source":{"kind":"parcha-original"},"status":"sample","exam":"inter"},{"id":"inter-chem11-stoi-03","v":1,"subject":"chemistry-11","chapter":"stoichiometry","difficulty":1,"stem":"The mass of one mole of carbon dioxide (CO₂) is:","options":["28 g","32 g","12 g","44 g"],"answer":3,"explain":{"en":"Molar mass of CO₂ = 12 + (2 × 16) = 44 g/mol, so one mole weighs 44 g.","ur":"CO₂ کا مولر ماس = 12 + (2 × 16) = 44 g/mol، اس لیے ایک مول کا وزن 44 g ہے۔"},"source":{"kind":"parcha-original"},"status":"sample","exam":"inter"},{"id":"inter-chem11-stoi-04","v":1,"subject":"chemistry-11","chapter":"stoichiometry","difficulty":2,"stem":"The limiting reactant in a reaction is the one that:","options":["Is present in the largest mass","Is used up first and limits the amount of product","Is left over at the end","Acts as a catalyst"],"answer":1,"explain":{"en":"The limiting reactant runs out first, so it decides how much product can form; the other reactant is left in excess. Compare mole ratios, not masses, to find it.","ur":"محدود کرنے والا ری ایکٹنٹ پہلے ختم ہو جاتا ہے اور یہی طے کرتا ہے کہ کتنی پیداوار بنے گی؛ دوسرا زیادہ رہ جاتا ہے۔ اسے ماس سے نہیں، مول کے تناسب سے پہچانیں۔"},"source":{"kind":"parcha-original"},"status":"sample","exam":"inter"},{"id":"inter-chem11-stoi-05","v":1,"subject":"chemistry-11","chapter":"stoichiometry","difficulty":2,"stem":"How many molecules are there in 0.5 mol of a gas?","options":["3.011 × 10²³","6.022 × 10²³","1.204 × 10²⁴","3.011 × 10²²"],"answer":0,"explain":{"en":"Number of molecules = moles × Avogadro's number = 0.5 × 6.022 × 10²³ = 3.011 × 10²³.","ur":"مالیکیولز کی تعداد = مول × ایووگیڈرو نمبر = 0.5 × 6.022 × 10²³ = 3.011 × 10²³۔"},"source":{"kind":"parcha-original"},"status":"sample","exam":"inter"},{"id":"inter-chem11-stoi-06","v":1,"subject":"chemistry-11","chapter":"stoichiometry","difficulty":2,"stem":"For 2H₂ + O₂ → 2H₂O, how many moles of water form from 4 mol of H₂ with excess oxygen?","options":["2","8","1","4"],"answer":3,"explain":{"en":"The equation gives 2 mol H₂ → 2 mol H₂O, a 1:1 ratio. So 4 mol H₂ gives 4 mol H₂O.","ur":"مساوات کے مطابق 2 مول H₂ سے 2 مول H₂O بنتا ہے، یعنی 1:1۔ اس لیے 4 مول H₂ سے 4 مول H₂O بنے گا۔"},"source":{"kind":"parcha-original"},"status":"sample","exam":"inter"}]}