Answer:
8.8g of Al are necessaries
Explanation:
Based on the reaction, 2 moles of Al are required to produce 3 moles of hydrogen gas.
To solve this question we must find the moles of H2 in 11L at STP using PV = nRT. With these moles we can find the moles of Al required and its mass as follows:
<em>Moles H2:</em>
PV = nRT; PV/RT = n
<em>Where P is pressure = 1atm at STP; V is volume = 11L; R is gas constant = 0.082atmL/molK and T is absolute temperature = 273.15K at STP</em>
Replacing:
1atm*11L/0.082atmL/molK*273.15K = n
n = 0.491 moles of H2 must be produced
<em />
<em>Moles Al:</em>
0.491 moles of H2 * (2mol Al / 3mol H2) = 0.327moles of Al are required
<em />
<em>Mass Al -Molar mass: 26.98g/mol-:</em>
0.327moles of Al * (26.98g / mol) = 8.8g of Al are necessaries
Answer:
They are 1.204×10^24 atoms of hydrogen present in 18 grams of water. In order to calculate this,it is necessary to compute the number of hydrogen moles present in the sample.
<span>At 20g with half-life of 5 minutes there would be 10g leftover in 5 minutes. In 10 mins, there would be 5g leftover. Half-life is actually what it says, it refers to time it takes for half of the active elements, etc to break down at which time the potency of the "product" is half as strong. This term is used mainly with radioactive items or medicines.</span>
Opportunity cost
Opportunity cost is the benefit, profit or value that could have been received or obtained but instead given up in favor of another alternative or course of action. Every situation has several alternatives and every resource has several alternative uses as well. Thus, every decision comes with it an opportunity cost. <span>
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