Answer:
(1) 0.0016 mol/L
Explanation:
Let the concentration of alcohol after 3.5 hours be y M
The reaction follows a first-order
Rate = ky^0 = change in concentration/time
k = 6.4×10^-5 mol/L.min
Initial concentration = 0.015 M
Concentration after 3.5 hours = y M
Time = 3.5 hours = 3.5×60 = 210 min
6.4×10^-5y^0 = 0.015-y/210
y^0 = 1
0.015-y = 6.4×10^-5 × 210
0.015-y = 0.01344
y = 0.015 - 0.01344 = 0.00156 = 0.0016 mol/L (to 4 decimal places)
Molecular clocks because the m<span>easure changes in DNA or proteins to indicate degrees of relationship among species.Molecular clocks, together with evidence from the fossil record, allows scientists to estimate how long ago various groups of organisms diverged evolutionarily from one another</span>
Answer:
31.60% phosphorus
Explanation:
To find the percent by mass, you first calculate the total mass and then the mass of phosphorus, and finally divide phosphorus mass by total.
Phosphorus mass: the molar mass of P is 30.97 g/mol, and since there's 1 mole of P, we just have 30.97 g.
Total mass: we add all the molar masses of the components together.
We have 3 moles of H, so we multiply 3 by 1.008 g/mol = 3.024 g H.
We already calculated the mass of phosphorus: 30.97 g P.
We have 4 moles of O, so we multiply 4 by 16.00 g/mol = 64.00 g O.
The total is then the sum: 3.024 + 30.97 + 64.00 = 97.994 g ≈ 97.99 g
Now, to find the percentage, we take 30.97 g P and divide by 97.99:
30.97/97.99 ≈ 0.3160 ⇒ 31.60% P
Thus, the answer is 31.60% phosphorus.
Hope this helps!
In any redox reaction, the substance that undergoes reduction will 3) <span> gain electrons and have a decrease in oxidation number.</span>
D. plenty of water
First, the affected area is washed with plenty of water for 15-20 minutes. Then washed with a weak solution of sodium bicarbonate.
H⁺ + HCO₃⁻ → H₂O + CO₂
