Answer:
CO₃²⁻(aq) + 2H⁺(aq) → CO₂ (g) + H₂O (l)
Explanation:
The balanced reaction between Na2CO3 and HCl is given as;
Na₂CO₃ (aq) + 2 HCl (aq) → 2 NaCl (aq) + CO₂ (g) + H₂O (l)
The next step is o express the species as ions.
The complete ionic equation for the above reaction would be;
2Na⁺(aq) + CO₃²⁻(aq) + 2H⁺(aq) + 2Cl⁻(aq) → Na⁺(aq) + Cl⁻(aq) + CO₂ (g) + H₂O (l)
The next step is to cancel out the spectator ion ions; that is the ions that appear in both the reactant and product side unchanged.
The spectator ions are; Na⁺ and Cl⁻
The net ionic equation is given as;
CO₃²⁻(aq) + 2H⁺(aq) → CO₂ (g) + H₂O (l)
The law of definite proportions would state that a hydrate always contain exactly the same proportion of salt and water by mass.
strictly speaking, the law of definite proportion states that a compound always
contains exactly the same proportion of elements by mass.
But the law is often applied to groupings of elements in compound.
Hydrates are salt that have a certain amount of water asa part of their structure.
The water is chemically combined with the compound in a definite ratio.
Answer:
A) 2.69 M
B) 0.059
Explanation:
A) We have:
33.8% solute by mass= 33.8 g solute/100 g solution
molarity = mol solute/ 1 L solution
molarity=
x
x
x 
molarity= 2.69 mol solute/L solution = 2.69 M
B) We know that there are 33.8 g of solute in 100 g of solution.
As the total solution is compounded by solute+solvent (in this case, solvent is water), the mass of water is the difference between the mass of the total solution and the mass of solute:
mass of water= 100 g - 33.8 g = 66.2 g
Now, we calculate the number of mol of both solute and water:
mol solute= 33.8 g solute x
= 0.232 mol
mol H20= 66.2 g H₂O x 
Finally, the mol fraction of solute (Xsolute) is calculated as follows:
Xsolute=
Xsolute= 0.059
Answer:
0.752 J/g*K
Explanation:
The heat lost by the alloy (which is negative) must be equal to the heat gained by the water and the coffee cup:
-Qa = Qw + Qc
-ma*ca*ΔTa = mw*cw*ΔTw + C*ΔTc
Where, m is the mass, c is the specific heat capacity, C is the heat capacity of the coffee cup, ΔT is the change in temperature, a represents the alloy, and w the water.
The coffee cup has initial temperature equal to the water, then:
-30.5*ca*(31.1 - 95.0) = 49.3*4.184*(31.1 - 24.3) + 9.2*(31.1 - 24.3)
1948.95ca = 1465.20
ca = 0.752 J/g*K