What's the mass of 7.61 x 10^24 molecules of Magnesium sulfate heptahydrate?
1400 g
1900 g
2500 g
31009

Mass = 3100 g

Explanation:

Given data:

Mass of MgSO₄.7H₂O = ?

Number of molecules = 7.61×10²⁴ molecules

Solution:

First of all we will calculate the number of moles of MgSO₄.7H₂O by using Avogadro number.

1 mole contain 6.022×10²³ molecules

7.61×10²⁴ molecules × 1 mol  / 6.022×10²³ molecules

1.26×10¹ mol

12.6 moles

Mass of MgSO₄.7H₂O:

Mass = number of moles × molar mass

Molar mass of MgSO₄.7H₂O = 246 g/mol

Mass = 12.6 mol × 246 g/mol

Mass = 3100 g

answer; natural resources;

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.