The total energy can be found by adding the different energies:
628 + 15,600 + 712
= 16.94 kJ
1. Answer;
Copper (ii) carbonate.
The name of the compound CuCO3 is copper (ii) carbonate.
Explanation;
Cu is the chemical symbol for the copper and CO3 is the chemical symbol for the carbonate group and each one of them has valency of two. Therefore, a compound CuCO3 is formed.
2. Answer;
Yes
Ca2+ reacted with Na2S to form CaS and Na+
Explanation:
Calcium ions reacts with sodium sulfide to form calcium sulfide and sodium ions.
For example; a salt of calcium, calcium carbonate reacts with sodium sulfide to form sodium carbonate and calcium sulfide.
3. Answer;
NaCl and Ag+ do not form a product
Explanation;
The reaction between sodium chloride and silver metal will not take place. This is because silver (Ag) is less reactive than sodium metal and therefore cannot displace sodium from its salt. In other words, silver metal is lower in the reactivity series as compared to sodium metal which indicates sodium metal is more reactive than silver.
4. Answer;
Formation of a white precipitate ; this indicates that silver sulfide is insoluble in water.
Explanation;
When an aqueous solution containing Ag+ ions is added to aqueous solution of sodium sulfide (Na2S), there will be formation of white precipitate. Formation of white precipitate indicates that a reaction has taken place to form a water insoluble compound. The water insoluble compound occurs as a precipitate. The white precipitate is silver sulfide (Ag2S)
2 Ag+ (aq) + Na2S(aq) ----- Ag2S (s) + 2 Na+ (aq)
Answer: pH=12.69
Explanation:
Initial 0.12 0 0
Eqm 0.12-x x x
![K_a=\frac{[H^+][F^-]}{[HF]}](https://tex.z-dn.net/?f=K_a%3D%5Cfrac%7B%5BH%5E%2B%5D%5BF%5E-%5D%7D%7B%5BHF%5D%7D)
(neglecting small value of x in comparison to 0.12)
Moles of 
0.06 moles of NaOH will give 0.06 moles of ![[OH^-]](https://tex.z-dn.net/?f=%5BOH%5E-%5D)
Now 
moles of 
will be neutralized by moles of 
and 
moles of will be left.
Molarity of 
![pOH=-\log[OH^-]=-\log[0.049]=1.31](https://tex.z-dn.net/?f=pOH%3D-%5Clog%5BOH%5E-%5D%3D-%5Clog%5B0.049%5D%3D1.31)
pH = 14 - pOH= 14 - 1.31 = 12.69
Answer:
Mg₃N₂
Explanation:
The empirical formula of a chemical compound is defined as the simplest positive integer ratio of atoms present in a compound. Using molecular mass of Mg (24,305g/mol) and mass of nitrogen (14,006g/mol), moles of each element are:
0,73g × (1mol / 24,305g) = 0,03 moles of Mg
0,28g × (1mol / 14,006g) = 0,02 moles of N
Dividing each value in 0,01 to obtain natural numbers:
0,03 moles of Mg / 0,01 = 3
0,02 moles of N / 0,01 = 2.
Thus, empirical formula is: <em>Mg₃N₂</em>
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I hope it helps!
Answer:
20% of phosphorus
Explanation:
A fertilizer is used to improve the fertility of soils. Most fertilizers contains the element nitrogen, phosphorus and potassium.
They are often designated NPK fertilizers.
Now we know that the numbers 10-20-20 depicts the nitrogen-phosphorus and potassium content of the fertilizer.
From the designation,
The actual percentage is 20% of phosphorus.
10% of nitrogen
20% of potassium
