उत्तरों सहित नर्सिंग प्रवेश परीक्षाओं के लिए रसायन विज्ञान वर्कशीट

What is the half-life of a radioactive isotope?

1. AHalf the time it takes for all the atoms to decay
2. BThe time taken for the mass of a sample to double in size
3. CHalf the number of protons in the nucleus
4. DThe time taken for half of the radioactive atoms in a sample to decay

What are the units of molarity?

1. AMoles of solute per kilogram of the solvent used
2. BGrams of solute per litre of solution (g/L)
3. CGrams of solute per 100 g of solution
4. DMoles of solute per litre of solution (mol/L)

What does the coefficient 3 in "3H₂O" mean?

1. AEach molecule of water contains three hydrogen atoms
2. BThere are three molecules (or moles) of water
3. CWater has a charge of 3
4. DEach water molecule has three oxygen atoms

What is the molar mass of sodium chloride, NaCl (Na = 23, Cl = 35.5 g/mol)?

1. A81.5 g/mol
2. B23 g/mol
3. C58.5 g/mol
4. D12.5 g/mol

How does electronegativity change going down a group?

1. AIt decreases
2. BIt stays the same
3. CIt doubles with each period
4. DIt increases

Uranium-235 and uranium-238 both have 92 protons. How many more neutrons does an atom of uranium-238 have?

1. A0
2. B146
3. C3
4. D92

Using PV = nRT with R = 0.082 L·atm/(mol·K), how many moles of gas are in 24.6 L at 1 atm and 300 K?

1. A1 mol
2. B0.5 mol
3. C2 mol
4. D300 mol

What is (8 × 10⁶) ÷ (2 × 10⁻²)?

1. A4 × 10⁴
2. B4 × 10⁸
3. C16 × 10⁴
4. D4 × 10⁻¹²