The blank is filled by Na₂SO₄, and the complete equation for the double displacement reaction is:
Na₂SO₄ + BaCl₂ = BaSO₄ + 2 NaCl
<h3>What is a double displacement reaction?</h3>
It is a reaction in which both reactants exchange anions and cations.
Let's consider the following incomplete double displacement reaction.
_____ + BaCl₂ = BaSO₄ + 2 NaCl
If we compare the left and right sides, we can see that the missing ions in the left side are Na⁺ and SO₄²⁻. Thus, the missing compound is Na₂SO₄. The complete equation is:
<span><span>Law of Conservation of Mass - "The total mass after a chemical reaction is exactly the same as the mass before"</span></span><span> </span>
Taking into account the definition of calorimetry, 0.0185 moles of water are required.
<h3>Calorimetry</h3>
Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.
Sensible heat is defined as the amount of heat that a body absorbs or releases without any changes in its physical state (phase change).
So, the equation that allows to calculate heat exchanges is:
Q = c× m× ΔT
where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.
<h3>Mass of water required</h3>
In this case, you know:
Heat= 92.048 kJ
Mass of water = ?
Initial temperature of water= 34 ºC
Final temperature of water= 100 ºC
Specific heat of water = 4.186
Replacing in the expression to calculate heat exchanges:
92.048 kJ = 4.186 × m× (100 °C -34 °C)
92.048 kJ = 4.186 × m× 66 °C
m= 92.048 kJ ÷ (4.186 × 66 °C)
<u><em>m= 0.333 grams</em></u>
<h3>Moles of water required</h3>
Being the molar mass of water 18 , that is, the amount of mass that a substance contains in one mole, the moles of water required can be calculated as:
When liquid water is cooled, it contracts until a temperature of approximately 4 degrees Celsius is reached. After that, it expands slightly until it reaches the freezing point, and then when it freezes it expands by approximately 9%. When water freezes, water molecules form a crystalline structure maintained by hydrogen bonding. Ice is less dense than water because the orientation of hydrogen bonds causes molecules to push farther apart, which lowers the density.