In a solid, the particles (ions, atoms or molecules) are closely packed together. The forces between particles are strong so that the particles cannot move freely but can only vibrate. ... There are various different crystal structures, and the same substance can have more than one structure (or solid phase).
An increase in the kinetic energy of the particles in a closed system
How many grams of Ca(OH)2 are necessary to prepare 450mL of 2.25M solution?
Molality = 2.25 M or 2.25 mole/L
Solvent = 450 ml (change it to liter by diving 1000) = .45 L
grams of Ca(OH)₂ = ? unknown
We need to solve first the mole of Ca(OH)₂ using the formula
molarity = moles of solute / liters of solution.
molarity = moles of solute / liters of solution
2.25 mol/L = moles of solute / .45 L
2.25 mol/L × .45 mol/L = moles of solute
1.012 mol = moles of solute
Convert 1.012 mol of Ca(OH)₂ to grams
Note: 1 mole of Ca(OH)₂ is equal to 74.09 g
1.012 mole of Ca(OH)₂ × 74.09 g / 1 mole = 74.98 grams
It needs 74.98 grams of Ca(OH)₂
Hope it helps...=)