Shape and size doesn't affect the density of an object but temperature does affect the density of an object because the molecules act differently in different temps.
The Equation of reaction
C + O2 === CO2
First Blank spot would be
---- 3.5moles of O2
2nd spot
Up.... 1mole of CO2
Down ---- 2moles of Oxygen atoms
3rd spot
Up... --- 22.4L of CO2(1mole of any gas at STP contains 22.4L)
Down---- 1mole of CO2
Final answer --- 3.5 x 1/2 x 22.4
=39.2L of CO2
Potassium Iodide or KI is an ionic compound and dissolves to water since the two are polar substances. Like dissolves like. As KI is dissolved into water, the KI molecules dissociates into ions, the K+ and I- ions. Water molecules can stabilize these ions. The K+ ions attracts the negative side of H2O molecules which is the oxygen side while the I- ions attracts the positive side of H2O molecules or the hydrogen side.
Answer: D. The number of molecules having Er or greater doubles.
Explanation: As the temperature increases from 20°C to 30°C, the number of molecules with maximum energy decreases, but the number of effective collisions which result into the formation of product doubles.
This is due to doubling of molecules which possess energy equal to or greater than 
which means now double number of molecules will be able to cross the energy barrier and hence the formation of product increases and hence the rate increases to double.
