The answer is the third one because density is mass divided by volume so 80 divided by 10 is 8
Answer:
algun moderador puede acabar a este otro este me borró respuesta que no debió borrar
Mg reaction with O₂ gas will produce MgO so the equation will be
2Mg+O₂⇒2MgO. (You have to find the equation in order two figure out the number of moles of O₂ that will react with 1 mole of MgO).
The first step is to find the number of moles of Mg in 4.03g of Mg. You can do this by dividing 4.03g Mg by its molar mass (which is 24.3g/mol) to get 0.1658mol Mg. Then you have to find the number of moles of O₂ that will react with 0.1658mol Mg. To do this you need to use the fact that 1mol O₂ will react with 2mol Mg (this reatio is from the chemical equation) so you have to multiply 0.1658mol Mg by (1mol O₂)/(2mol Mg) to get 0.0829mol O₂. From here you would usually use PV=nRT and solve for V However, the question tells us that we are at STP, that means you can use the fact that 22.4L of gas is 1 mol of gas at STP. Using that information we can find the volume of O₂ gas by mulitlying 0.0829mol O₂ by 22.4L/mol to get 1.857L which equals 1857mL.
therefore, 1857mL of O₂ gas will react with 4.03g of Mg.
I hope this helps. Let me know in the comments if anything is unclear.
Answer:
The volume of carbon dioxide gas generated 468 mL.
Explanation:
The percent by mass of bicarbonate in a certain Alka-Seltzer = 32.5%
Mass of tablet = 3.45 g
Mass of bicarbonate =
Moles of bicarbonate ion = 
According to reaction, 1 mole of bicarbonate ion gives with 1 mole of carbon dioxide gas , then 0.01840 mole of bicarbonate ion will give:
of carbon dioxide gas
Moles of carbon dioxide gas n = 0.01840 mol
Pressure of the carbon dioxide gas = P = 1.00 atm
Temperature of the carbon dioxide gas = T = 37°C = 37+273 K=310 K
Volume of the carbon dioxide gas = V
(ideal gas equation)
1 L = 1000 mL
0.468 L =0.468 × 1000 mL = 468 mL
The volume of carbon dioxide gas generated 468 mL.
