Answer:
The specific heat of the metal is 0,50 J/gºC
Explanation:
Assume that no heat is lost to the surroundings
(Q = m . C . ΔT)metal + (Q = m . C . ΔT)water = 0
Let's replace our values.
55g . C . (18,7ºC - 75ºC) + 100g . 4,184 J/g·°C . (18,7ºC - 15ºC) = 0
55g . C . -56,3 ºC + 418,4J/·°C . 3,7ºC = 0
-3096,5 gºC . C + 1548,08 J = 0
1548,08 J = 3096,5 gºC . C
1548,08 J / 3096,5 gºC = C = 0,50 J/gºC
Depending in the category of the Hurricane, you make experience different levels of wind power and destruction. Hurricanes only have 5 categories ranking from Category 1 to Category 5. The smallest category is category 1 making category 5 the largest. The bigger the category, the more wind or destruction you'll experience.
Answer:
Explanation:
- For the balanced reaction:
<em>4Fe(s) + 3O₂(g) → 2Fe₂O₃(s).</em>
It is clear that 4 mol of Fe react with 3 mol of O₂ to produce 2 mol of Fe₂O₃.
- Firstly, we need to calculate the no. of moles of 35.8 grams of Fe metal:
no. of moles of Fe = mass/molar mass = (35.8 g)/(55.845 g/mol) = 0.64 mol.
- Now, we can find the no. of moles of O₂ is needed to react with the proposed amount of Fe:
<em><u>Using cross multiplication:</u></em>
4 mol of Fe is needed to react with → 3 mol of O₂, from stichiometry.
0.64 mol of Fe is needed to react with → ??? mol of O₂.
∴ The no. of moles of O₂ needed = (3 mol)(0.64 mol)/(4 mol) = 0.48 mol.
- Finally, we can get the volume of oxygen using the information:
<em>It is known that 1 mole of any gas occupies 22.4 L at standard P and T (STP).</em>
<em></em>
<em><u>Using cross multiplication:</u></em>
1 mol of O₂ occupies → 22.4 L, at STP conditions.
0.48 mol of O₂ occupies → ??? L.
∴ The no. of liters of O₂ = (0.48 mol)(22.4 L)/(1 mol) = 10.752 L.
3Si + 2N2 --> Si3N4 (as given)
n(Si) = m/MM = 38.25/28.085 = 1.3619 mol
n(N2) = 14.33/2*14.007 = 0.5115 mol
Therefore, N2 is limiting and Si is in excess
The molar ratio of 2N2:Si3N4 is 2:1
So, 0.0575 mol of silicon nitride is formed (dividing 0.5115 by 2)
m of silicon nitride= n*mm = 0.0575*140.283 = 8.06627... g
= 8.066g (4 significant figures)
(hopefully it is right, but double check in case i did something wrong) :)
Answer:
+5
Explanation:
The oxidation number of phosphorus can be obtained as follows:
H4P2O7 = 0
4(+1) + 2P + 7(—2) = 0
4 + 2P —14 = 0
Collect like terms
2P = 14 — 4
2P = 10
Divide both side by 2
P = 10/2
P = +5
The oxidation number of phosphorus is +5
