Answer:
a) Ba(OH)₂.8H₂O(s) + <em>2 </em>NH₄SCN(s) → Ba(SCN)₂(s) +<em>10</em> H₂O(l) + <em>2</em> NH₃(g)
b) 3.14g must be added
Explanation:
a) For the reaction:
Ba(OH)₂.8H₂O(s) + NH₄SCN(s) → Ba(SCN)₂(s) + H₂O(l) + NH₃(g)
As you see, there are 8 moles of water in reactants and 2 moles of oxygen in octahydrate, thus, water moles must be 10:
Ba(OH)₂.8H₂O(s) + NH₄SCN(s) → Ba(SCN)₂(s) +<em>10</em> H₂O(l) + NH₃(g)
To balance hydrogens, the other coefficients are:
Ba(OH)₂.8H₂O(s) + <em>2 </em>NH₄SCN(s) → Ba(SCN)₂(s) +<em>10</em> H₂O(l) + <em>2</em> NH₃(g)
b) As you see in the balanced reaction, 1 mole of barium hydroxide octahydrate reacts with 2 moles of NH₄SCN. 6.5g of Ba(OH)₂.8H₂O are:
6.5 g × (1mol / 315.48g) =<em> 0.0206moles of Ba(OH)₂.8H₂O</em>. Thus, moles of NH₄SCN that must be used for a complete reaction are:
0.0206moles of Ba(OH)₂.8H₂O × ( 2 mol NH₄SCN / 1 mol Ba(OH)₂.8H₂O) = <em>0.0412moles of NH₄SCN</em>. In grams:
0.0412moles of NH₄SCN × ( 76.12g / 1mol) = <em>3.14g must be added</em>
Ink can be separated into black and other color pigments. This can be done on filter paper by dotting the marker just above the edge and adding ethyl alcohol, which drags the pigments separately across the paper.
Answer: Mass of 
required to form 930 kg of iron is 1328 kg
Explanation:
To calculate the number of moles, we use the equation:
.....(1)
For iron:
Given mass of iron = 930 kg = 930000 g (1kg=1000g)
Molar mass of iron = 56 g/mol
Putting values in equation 1, we get:
The chemical equation for the production of iron follows:
By Stoichiometry of the reaction:
2 moles of iron are produced by = 1 mole of
So, 16607 moles of iron will be produced by = 
of
Now, calculating the mass of from equation 1, we get:
Mass of = 
Thus mass of required to form 930 kg of iron is 1328 kg
Answer:
c. Can't decide with information given.
Explanation:
The chemical and physical processes can be classified as endothermic or exothermic. The first one happens when the system absorbs heat, so the temperature of the surroundings will decrease, and the other one happens when the system releases heat, then the temperature of the surrounds will increase.
Precipitation is the formation of a solid in a solution. The process can happen with absorption or release of heat, it depends on the substance. So, with the information given it's impossible to say it.
Organic or inorganic is the answer
