How many moles are found in 10.5 g of Pb?

Number of moles = 0.05 mol

Explanation:

Given data:

Mass of Pb = 10.5 g

Number of moles of Pb = ?

Solution:

Formula:

Number of moles = mass/molar mass

Molar mass of Pb is 207.2 g/mol.

Now we will put the values in formula.

Number of moles = 10.5 g/207.2 g/mol

Number of moles = 0.05 mol

i just learnt this recently but i need to look through my notes again

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.