Answer:
-26.125 kj
Explanation:
Given data:
Mass of water = 250.0 g
Initial temperature = 30.0°C
Final temperature = 5.0°C
Amount of energy lost = ?
Solution:
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = T2 - T1
ΔT = 5.0°C - 30.0°C
ΔT = -25°C
Specific heat of water is 4.18 j/g.°C
Now we will put the values in formula.
Q = m.c. ΔT
Q = 250.0 g × 4.18 j/g.°C × -25°C
Q = -26125 j
J to kJ
-26125 j ×1 kj /1000 j
-26.125 kj
Answer:
+4
Explanation:
In PbO2, oxygen exhibits an oxidation number of -2 (since it's not a peroxide or superoxide):
Let the oxidation number of Pb be x. Then, for the compound to be neutral, the oxidation numbers of all atoms should add up to zero.
⇒ x + (−2) + (−2) = 0
x = +4
So the oxidation no. of Pb is +4.
I hope this helps.
Answer:
Explanation:
The nitrates of Bi,Sn and Cd is ruled out because their sulfides are insoluble in acidic medium.
Nitrates of Ni or Co may be present because their sulfides are insoluble in basic medium. The presence of other nitrates are ruled out.
1 mole of water = 18 grams (you can find this by finding mass of two hydrogen and one oxygen which is (1*2) + 16 = 18)
1.8 grams = 0.1 moles
1 H2O molecule has 10 electrons so 0.1 moles can be computed as:
(6.023*10^23)*(0.1)*10 = 6.023*10^23 electrons
The chemical reaction that the situation demonstrates would be a double replacement reaction.
In double replacement reactions, the two reactants participating in the reaction are similarly built in terms of their chemical bonds and they exchange ions to form the products of the reaction. Two products are also formed from the two reactants.
It is as opposed to single replacement reactions in which the two reactants are not similar bond-wise. One of the reactants replaces or displaces one of the ions in another reactant.
In this case, the situation can be represented as follows:
Amanda-Janice + Deja-Eden ----> Amanda-Eden + Deja-Janice
Thus, it is a form of double replacement reaction.
More on double replacement reactions can be found here: brainly.com/question/392491?referrer=searchResults