With a partner, look at the stone bricks used to build this building and think about how they changed over time. What caused the
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We have the following balanced equation:
They also give us the heat of reaction equal to -764 kJ, i.e. it is an exothermic reaction.
By observing the reaction, we can deduce that for this heat to be generated, one mole of methanol is needed. Now let's see how many grams that mole of methanol equals. We will use the molecular weight equal to 32.04 g/mol
Now we know the grams of methanol that generate 764 kJ, because the heat of reaction is directly proportional to the mass of the reactants, we can apply a rule of three to know the grams needed to produce a heat of reaction equal to 701 kJ:
So, 29.4 g of methanol must be found to produce 701 kJ of heat
That will make a gold-202 nucleus.
<h3>Explanation</h3>Refer to a periodic table. The atomic number of mercury Hg is 80.
Step One: Bombard the with a neutron
. The neutron will add 1 to the mass number 202 of
. However, the atomic number will stay the same.
- New mass number: 202 + 1 = 203.
- Atomic number is still 80.
.
Double check the equation:
- Sum of mass number on the left-hand side = 202 + 1 = 203 = Sum of mass number on the right-hand side.
- Sum of atomic number on the left-hand side = 80 = Sum of atomic number on the right-hand side.
Step Two: The nucleus loses a proton
. Both the mass number 203 and the atomic number will decrease by 1.
- New mass number: 203 - 1 = 202.
- New atomic number: 80 - 1 = 79.
Refer to a periodic table. What's the element with atomic number 79? Gold Au.
.
Double check the equation:
- Sum of mass number on the left-hand side = 203 = 202 + 1 = Sum of mass number on the right-hand side.
- Sum of atomic number on the left-hand side = 80 = 79 + 1 = Sum of atomic number on the right-hand side.
A gold-202 nucleus is formed.