Answer:
-1071 Joules
Explanation:
The Joule was introduced as the SI unit for energy in 1925. One calorie is equal to approximately 4.184 joules(J). This is a conversion factor that we can write two ways:
(1cal/4.184J) or (4.184J/1cal)
(265 cal)*(4.184J/1cal) = 1071 J
Since the energy is leaving the system, it should be written with a minus sign: -1071J
Hey there
the answers are
A.
and
D. He could spray the fire extinguisher in the opposite direction of the space station
hope this helps
Hey there!:
Molar mass of Mg(OH)2 = 58.33 g/mol
number of moles Mg(OH)2 :
moles of Mg(OH)2 = 30.6 / 58.33 => 0.5246 moles
Molar mass of H3PO4 = 97.99 g/mol
number of moles H3PO4:
moles of Mg(OH)2 = 63.6 / 97.99 => 0.649 moles
Balanced chemical equation is:
3 Mg(OH)2 + 2 H3PO4 ---> Mg3(PO4)2 + 6 H2O
3 mol of Mg(OH)2 reacts with 2 mol of H3PO4 ,for 0.5246 moles of Mg(OH)2, 0.3498 moles of H3PO4 is required , but we have 0.649 moles of H3PO4, so, Mg(OH)2 is limiting reagent !
Now , we will use Mg(OH)2 in further calculation .
Molar mass of Mg3(PO4)2 = 262.87 g/mol
According to balanced equation :
mol of Mg3(PO4)2 formed = (1/3)* moles of Mg(OH)2
= (1/3)*0.5246
= 0.1749 moles of Mg3(PO4)2
use :
mass of Mg3(PO4)2 = number of mol * molar mass
= 0.1749 * 262.87
= 46 g of Mg3(PO4)2
Therefore:
% yield = actual mass * 100 / theoretical mass
% = 34.7 * 100 / 46
% = 3470 / 46
= 75.5%
Hope that helps!
Answer:
Left and right: two forces
Total: four forces
Explanation:
If it's just the forces that they are using it would be two the force of each person's hand on the other. However there is also gravity pulling down on their hand but they use another force to pull it up which you can call the normal force.
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