A chemical compound contains nitrogen and oxygen in a mass ratio of 28 g to 80 g, respectively. What is the empirical formula of this compound_________________?
Show answer Hide answer
Answer: B. N2O5
Explanation
Empirical formulas express the simplest whole-number atomic ratio of elements within a chemical compound. Dividing the given mass of nitrogen by its atomic weight yields two moles of nitrogen atoms. Dividing the oxygen mass by its atomic weight gives five moles of oxygen, producing N2O5. Atomic weights of nitrogen and oxygen are approximately fourteen and sixteen grams per mole respectively. Determining chemical formulas from mass percentages is a fundamental skill in analytical chemistry. Dinitrogen pentoxide is a well-known covalent chemical oxide compound containing these exact proportions.
Laboratory chemical analysis relies on mass ratios to determine unknown compound molecular structures. Industrial synthesis of nitric acid and nitrates depends on accurate stoichiometry of nitrogen oxides. Understanding empirical formulas helps predict reaction behaviors in chemical manufacturing plants. Option A N2O4 features four oxygen atoms, which would correspond to a different oxygen mass ratio. Option C N2O3 contains three oxygen atoms, yielding a lower mass ratio than given in the problem statement. Option D none of these is incorrect because N2O5 matches the calculated mole ratio perfectly.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. Specific ____________ remains unchanged during phase transformations like sublimation, melting, or vaporization?
Show answer Hide answer
Answer: D. Gibbs free energy
First-order phase transitions involve the coexistence of two phases at a fixed temperature and pressure. At this specific equilibrium point, the chemical potential of both coexisting phases is identical. Since chemical p...
Q2. A sample of gas at 0°C is cooled at constant pressure until its volume is halved. What will be the final temperature of the gas_______________?
Show answer Hide answer
Answer: A. -136.5°C
Charles law states that gas volume is directly proportional to its absolute temperature at constant pressure. Halving the gas volume at constant pressure requires halving its absolute temperature value. Converting the fi...
Q3. A gas occupying 283 c.c. at 10°C is heated to 20°C at constant pressure; its new volume will be __________ c.c?
Show answer Hide answer
Answer: C. 293
Charles's law states that gas volume is directly proportional to absolute temperature at constant pressure. Temperatures must be converted to the absolute Kelvin scale by adding two hundred seventy-three. Calculating (28...
Q4. _____________ kg of CaC03 subjected to thermal decomposition yields 56 kg of CaO?
Show answer Hide answer
Answer: B. 100
Thermal decomposition of calcium carbonate produces solid calcium oxide and carbon dioxide gas. Stoichiometric calculation shows one hundred kilograms of reactant yields fifty six kilograms of product. Molecular weight c...
Q5. 1 BTU/ft3 is approximately equal to how many kcal/m3 _____________?
Show answer Hide answer
Answer: B. 9
Converting energy density units from British Thermal Units per cubic foot to metric units requires specific factors. Multiplication by the standard volumetric and thermal conversion factor yields approximately nine kcal...
Q6. A well water sample contains 140 gm/m3 of Ca2+ and 345 gm/m3 of Na+ ions. Express the total hardness in terms of equivalent CaCO3 in gm/m3 (using atomic weights Ca:40, Na:23, C:12, O:16) ?
Show answer Hide answer
Answer: A. 350
Total hardness is expressed in terms of equivalent calcium carbonate concentration. Calcium and magnesium ions contribute significantly to overall water hardness values. Calculations involve multiplying individual ion co...