Response:
9.606 g
Clarification:
Step 1: Write the balanced combustion equation
C₂H₆O(l) + 3 O₂(g) → 2 CO₂(g) + 3 H₂O(g)
Step 2: Determine the moles for 11.27 g of H₂O
The molar mass of H₂O is 18.02 g/mol.
11.27 g × (1 mol/18.02 g) = 0.6254 mol
Step 3: Find the moles of C₂H₆O that produced 0.6254 moles of H₂O
The ratio of C₂H₆O to H₂O is 1:3. Thus, the moles of C₂H₆O are 1/3 × 0.6254 mol = 0.2085 mol
Step 4: Calculate the mass for 0.2085 moles of C₂H₆O
The molar mass of C₂H₆O is 46.07 g/mol.
0.2085 mol × 46.07 g/mol = 9.606 g
3 first significant figure
6 second significant figure
5 third significant figure
4 cannot exceed 5, so retain 5 instead of increasing it to 6
0.0365
145 hours.
Explanation: Riding a bicycle for one hour expends 505 kcal of energy. Given that one gram of body fat equals 7.70 kcal, and 1 pound of body fat is equivalent to 454 grams:
1 lb = 454 g; thus, 21 lb = 21 × 454/1 = 9534 g. Moreover, converting 9534 g of body fat gives us 9534 × 7.70 kcal/1 = 73411.8 kcal. If riding for one hour burns 505 kcal, then to lose 73411.8 kcal, it would require 73411.8 kcal x 1 hour/505 kcal = 145 hours.
Diethyl ether (DTH) and Tetrahydrofuran (THF).
Clarification:
- Grignard reactions react with water, resulting in the formation of alkanes. The presence of water leads to rapid decomposition of the reagent.
Therefore, solvents like anhydrous diethyl ether or tetrahydrofuran (THF), as well as poly(tetramethylene ether) glycol (PTMG), are used in experimental procedures to limit the exposure of Grignard reagents to air and moisture.
These solvents are chosen because the oxygen they contain stabilizes the magnesium reagent.
THF is a stable compound.
Answer:
B) Hyperbolic curve; substrate saturation
Explanation:
Enzymatic kinetics examines the rates of reactions catalyzed by enzymes. These studies offer insights into the mechanism of the catalytic reaction and enzyme specificity. Determining the reaction rate facilitated by an enzyme is generally straightforward, as purification or isolation of the enzyme is frequently unnecessary. Measurements are taken under optimal conditions for pH, temperature, and the presence of cofactors, utilizing saturating substrate concentrations. Under these circumstances, the observed reaction rate is the maximum velocity (Vmax). The rate can be measured by monitoring either product formation or substrate consumption.
Following the rate of product formation (or substrate consumption) over time yields the so-called reaction progress curve, or merely, reaction kinetics. This reacts as a hyperbolic curve
