Neco Model Questions Vol1 2019 Chemistry Question 2

A student measured the mass and volume of an unknown metallic solid using a graduated cylinder filled with water (water‑displacement method). The recorded data are: - Mass of the metal (m) = 45.0 g - Initial water volume = 30.0 mL - Final water volume after immersion = 35.0 mL The student is provided with the following density data for common metals (in g cm⁻³): | Metal | Density | |-------|---------| | Magnesium (Mg) | 1.74 | | Aluminum (Al) | 2.70 | | Iron (Fe) | 7.87 | | Copper (Cu) | 8.96 | | Zinc (Zn) | 7.14 | | Silver (Ag) | 10.5 | Using the experimental data and the table, the student must: a) Calculate the density of the unknown metal. b) Identify the metal by comparing the calculated density with the given values and justify the choice using periodic‑table trends (period and group). c) Using the atomic mass of the identified metal (Cu = 63.55 g mol⁻¹), calculate the number of moles present in the sample and estimate the total number of atoms (use Avogadro’s number 6.02 × 10²³ mol⁻¹).