Answer : Option E) 50 grams.
Explanation : According to the solubility curves the compound 
to dissolve at 50 °C in 100 mL of water will need 50 grams of the compound. It is clearly indicated in the graph which is marked with red that at 50°C approximately 50.4 grams of the compound will be needed to dissolved in 100 mL of water to form a solution.
Answer:
1. D 2. C 3. B
Explanation:
1. The product is always what is being yielded from the equation, or what is created. Since both 4H2O and 3CO2 are created from the reactants, they are both products of the reaction.
2. The Law of Conservation of Matter states that matter cannot be created, nor destroyed. Therefore, C is not true because new atoms cannot be created in a reaction.
3. The second formula is balanced, but the first is not
Explanation:
Methane molecule is depicted here
Explanation:
The net equation will be as follows.
So, we are required to find 
for this reaction.
Therefore, steps involved for the above process are as follows.
Step 1: Convert K from solid state to gaseous state
, 
= 89 kJ
Step 2: Ionization of gaseous K
, 
= 418 KJ
Step 3: Dissociation of 
gas into chlorine atom
.
, 
= 122 KJ
Step 4: Iozination of chlorine atom.
, 
= -349 KJ
Step 5: Add 
ion and 
ion formed above to get KCl
.
, 
= -717 KJ
Now, using Born-Haber cycle, value of enthalpy of the formation is calculated as follows.
= 89 + 418 + 122 - 349 - 717
= - 437 KJ/mol
Thus, we can conclude that the heat of formation of KCl is - 437 KJ/mol.
Answer:
27.98g/mol
Explanation:
Using ideal gas law equation;
PV = nRT
Where;
P = pressure (atm)
V = volume (L)
T = temperature (K)
n = number of moles (mol)
R = gas law constant (0.0821 Latm/molK)
According to the information given:
V = 2.5L
P = 1.4 atm
T = 282K
n = ?
Using PV = nRT
n = PV/RT
n = 1.4 × 2.5/0.0821 × 282
n = 3.5/23.1522
n = 0.151mol
Using the formula to calculate molar mass of the elemental gas:
mole = mass/molar mass
Molar mass = mass/mole
Molar mass = 4.23g ÷ 0.151mol
Molar mass = 27.98g/mol
