Missing question:<span> How many grams of oxygen are needed for complete combustion of the toluene?
Chemical reaction: </span>C₇H₈ + 9O₂ → 7CO₂ + 4H₂<span>O.
V(</span>C₇H₈) = 8,30 ml.
d(C₇H₈) = 0,867 g/ml.
n(C₇H₈) = V(C₇H₈) · d(C₇H₈).
m(C₇H₈) = 8,3 ml · 0,867 g/ml.
m(C₇H₈) = 7,19 g.
n(C₇H₈) = m(C₇H₈) ÷ M(C₇H₈).
n(C₇H₈) = 7,19 g ÷ 92,14 g/mol = 0,078 mol.
From chemical reaction: n(C₇H₈) : n(O₂) = 1 : 9.
n(O₂) = 9 · 0,078 mol = 0,702 mol.
m(O₂) = 0,702 mol · 32 g/mol = 22,5 g.
The MC1R gene provides instructions for making a protein called the melanocortin 1 receptor. This receptor plays an important role in normal pigmentation. The receptor is primarily located on the surface of melanocytes, which are specialized cells that produce a pigment called melanin.
Answer:
0.4 moles of KOH is required to neutralize 0.4 moles of HNO3.
Explanation:
The equation of the reaction is
KOH(aq) + HNO3(aq) ------> KNO3(aq) + H2O(l)
This is a neutralization reaction. A neutralization reaction is a reaction between an acid and a base to form salt and water only.
Having written the balanced chemical reaction equation, we can now solve the prob!em stoichiometrically.
From the balanced reaction equation;
1 mole of KOH is required to neutralize 1 mole of HNO3
Therefore x moles of KOH is required to neutralize 0.4 moles of HNO3
x= 1×0.4/1 = 0.4 moles
Therefore, 0.4 moles of KOH is required to neutralize 0.4 moles of HNO3.
I believe the answer is "After adding two substances together a new order is detected" because nearly all of the other answers suggest a chemical change has taken place. The reason I say "almost" is because answer two and four results in bubbles forming so the answer cannot be both. The only one to not clearly show a chemical change has occurred is the last answer.
