Answer:
70%
Explanation:
To find the percent yield, you need to (1) convert grams HCl to moles (via molar mass from periodic table), then (2) convert moles HCl to moles H₂ (via mole-to-mole ratio from equation), then (3) calculate the percent yield H₂ (via percent yield equation).
Zn (s) + 2 HCl (aq) --> ZnCl₂ (aq) + 1 H₂ (g)
Molar Mass (HCl): 1.008 g/mole + 35.45 g/mole
Molar Mass (HCl) = 36.458 g/mole
125 g HCl 1 mole HCl 1 mole H₂
--------------- x ------------------ x ------------------ = 1.7 moles H₂
36.458 g 2 moles HCl
(actual yield / theoretical yield) x 100% = percent yield
theoretical/calculated yield = 1.7 moles H₂
actual yield = 1.2 moles H₂
(1.2 moles H₂ / 1.7 moles H₂) x 100% = 71%
Therefore, the best percent yield of hydrogen produced is 70%.
Answer:
Tom is correct. The rate of reaction of Crystal violet and NaOH is first order with respect to NaOH, hence, a higher concentration of NaOH corresponds to a higher rate of reaction; a faster reaction.
This means the speed of cleaning depends on the concentration of the lye used.
Explanation:
The reaction between Crystal violet and NaOH, represented as
CV⁺ + OH⁻ → CVOH
It is a reaction that is know to turn the violet colour of the crystal violet colourless.
The rate of the reaction is also known to be second order; first order with respect to Crystal violet and first order with respect to NaOH.
This means that the rate of reaction is directly proportional to the concentration of NaOH provided all other parameters such as the rate constant and the concentration of Crystal violet are constant.
Hence, the reaction becomes faster with an increased concentration of NaOH.
So, Tom is right, concentrated lye solution would remove the stain faster.
Bob is wrong.
Hope this Helps!!!
Answer:
The correct answer is 0, 235 mol
Explanation:
We use the formula PV =nRT. The normal conditions of temperature and pressure are 273K and 1 atm, we use the gas constant = 0, 082 l atm / K mol:
1 atm x 5, 25l = n x 0, 082 l atm / K mol x 273 K
n= 1 atm x 5, 25l /0, 082 l atm / K mol x 273 K
n= 0, 235 mol
Answer:
Deep inside Earth, between the molten iron core and the thin crust at the surface, there is a solid body of rock called the mantle. When rock from the mantle melts, moves to the surface through the crust, and releases pent-up gases, volcanoes erupt.
Explanation: hot molten rock, ash, and gases escape from the volcano
