Answer:
a) 4869 kj will be released
b) 43.86 g of octane
Explanation:
The heat of combustion is the amount of heat released when one mole of a substance reacts with enough oxygen
since the heat of combustion is per mol of combustible substancewjat we are required to do in this problem is calculate number moles in the reactions although in a different manner
a) MW C3H6O = 158 g/ mol
mol C3H6O = 158 g × 1 mol/ 58.08 g
= 2.72 - 1790 kj / mol ×2.72 mol = 4869 kj
b) Here we are asked the mass of octane to produce 1950 kj of heat knowing that per mole of octane we get 5074.1 kj then
1 mol / 5074.1kj × 1950 kj= 0.384 mol
mass C8H18 = 0.384 mol × 114.23 g/ mol = 43.86 g
Answer:
a, d and e. are true.
Explanation:
The reaction that occurs is:
Na2CO3(aq) + CaCl2(aq) → CaCO3(s) + 2NaCl
In ideal conditions, the percent yield of the reaction must be 100%. All explanations about why the student could not collect all precipitate are right:
a. The combined reactants were not stirred before filtering the precipitate. Not stirring could not promote all the reaction. <em>TRUE.</em>
b. The student did not completely dry the precipitate before weighing it. If the student don't dry the precipitate, the mass of precipitate must be higher producing a percent yield > 100%. <em>FALSE.</em>
c. The precipitate was not washed prior to drying. Produce more mass. <em>FALSE.</em>
d. A rubber policeman was not used to scrape precipitate from the beaker. If the student doesn't collect all the precipitate the percent yield could be < 100%.. <em>TRUE.</em>
e. The filter paper was not wetted with water prior to filtering the precipitate. <em>TRUE. </em>If you don't wet the filter paper you can lose a part of precipitate from the walls of this one.
Answer:
The answer is: <u>Al2O3</u>
Explanation:
The data they give us is:
To find the empirical formula without knowing the grams of the compound, we find it per mole:
- 0.545 g Al * 1 mol Al / 27 g Al = 0.02 mol Al
- 0.485 g O * 1 mol O / 16 g O = 0.03 mol O
Then we must divide the results obtained by the lowest result, which in this case is 0.02:
- 0.02 mol Al / 0.02 = 1 Al
- 0.03 mol O / 0.02 = 1.5 O
Since both numbers have to give an integer, multiply by 2 until both remain integers:
Now the answer is given correctly:
Answer:
Glucose
Explanation:
Glucose molecule is the primary source of energy for most organisms where processes such as glycolysis starts and cellular respiration follows. Bodies of organisms can get energy from carbohydrates, proteins and fats with carbohydrates being the main component for energy where they are converted to glucose which is a form of sugar that reacts to affect blood sugar levels within an hour or two hours after eating.
The second answer option, table salt (NaCl) is incorrect because sodium added in food is vital for functioning of nerves and muscles. Additionally, it helps in fluid regulation and control of blood pressure/volume in the body.
The third answer , hydrochloric acid is not correct because presence of hydrochloric acid in the body helps in breaking down, digestion and absorption of nutrients.
The correct answer choices are : A and D.
