What mass of gold (au) contains the same number of atoms as 7.72g of aluminum (al) ? in units of g
no answer choices

55.16 gram of gold contain same number of atoms as 7.72 g Al contain.

Explanation:

Given data:

Mass of Al = 7.72 g

Mass of gold contain same number of atoms as 7.72 g Al contain = ?

Solution:

First of all we will determine the atoms of Al in 7.72 g.

Number of moles = mass/ molar mass

Number of moles = 7.72 g / 27 g/mol

Number of moles = 0.286 mol

Number of atoms:

0.286 mol × 6.022 ×10²³ atoms / 1 mol

1.72 ×10²³ atoms

Now we determine the mass of gold that contain 1.72 ×10²³ atoms:

1 mol =  6.022 ×10²³ atoms

1.72 ×10²³ atoms× 1 mol / 6.022 ×10²³ atoms = 0.28 mol

Mass of gold = number of moles × molar mass

Mass of gold =0.28 mol × 197 g/mol

Mass of gold = 55.16 g

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.

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