Answer: B
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Pb/pbco3*100
207/207+12+48
207/267*100
=77.53%
Answer: 
Explanation:
First we have to calculate the heat absorbed by bomb calorimeter
Formula used :
= heat absorbed by calorimeter = ?
= specific heat of = 10.69 kJ/K
= final temperature = 
= initial temperature = 
As heat absorbed by calorimeter is equal to the heat released by acetylene during combustion.
Thus 1.53 gram of acetylene releases heat of combustion = 258.7kJ
So, 26.04 g/mole of acetylene releases heat of combustion 
Therefore, the heat of combustion of acetylene is,
Answer:
A-Metals
Explanation:
because they have valence electrons
Answer:
3.47 × 10²³ C atoms
Solution:
Data Given:
Mass of Diamond = 48 mg = 0.048 g
M.Mass of Diamond = 12.01 g.mol⁻¹ (as it is purely Carbon)
Step 1: Calculate Moles of Diamond as,
Moles = Mass ÷ M.Mass
Putting values,
Moles = 0.048 g ÷ 12.01 g.mol⁻¹
Moles = 0.576 mol
Step 2: Calculate number of Carbon atoms,
As 1 mole of any substance contains 6.022 × 10²³ particles (Avogadro's Number) then the relation for Moles and Number of Carbon atoms can be written as,
Moles = Number of C Atoms ÷ 6.022 × 10²³ Atoms.mol⁻¹
Solving for Number of C atoms,
Number of C atoms = Moles × 6.022 × 10²³ Atoms.mol⁻¹
Putting value of moles,
Number of C atoms = 0.576 mol × 6.022 × 10²³ Atoms.mol⁻¹
Number of C atoms = 3.47 × 10²³ C atoms
