Calculate the mass of iron formed when 299g of iron (ii) oxide is reduced by excess carbon monoxide

Mass = 88.12 g

Explanation:

Given data:

Mass of iron oxide = 126 g

Mass of iron formed = ?

Solution:

Chemical equation:

Fe₂O₃ + 3CO    →      2Fe + 3CO₂

Number of moles of iron oxide:

Number of moles = mass/molar mass

Number of moles = 126 g/ 159.69 g/mol

Number of moles = 0.789 mol

Now we will compare the moles of iron with iron oxide.

                     Fe₂O₃           :             Fe

                        1                 :               2

                  0.789              :            2/1×0.789 = 1.578 mol

Mass of iron:

Mass = number of moles ×molar mass

Mass = 1.578 mol × 55.84 g/mol

Mass = 88.12 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.