Explanation:
Physical changes are the changes that does not lead to any change in chemical composition of a substance.
For example, mass, density, volume are all physical changes.
On the other hand, a change that leads to formation of a new compound by changing the chemical composition of reactants or combining atoms is known as a chemical change.
For example, combustion, toxicity, reactivity etc are all chemical changes.
Therefore, given changes are identified as follows.
- Coal burning : It is a combustion reaction. Hence, it is a chemical change.
- Ice melting : Physical state of water changes from solid to liquid. Hence, it is a physical change.
- mixing chocolate syrup with milk : No new compound is forming as there is no chemical reaction occurring. Hence, it is also a physical change.
- explosion of a firecracker : It shows reactivity of fire cracker. Hence, it is a chemical reaction.
- magnetizing of a screwdriver : It shows physical attraction between the magnet and screwdriver. Hence, it is a physical change.
Answer:
-767,2kJ
Explanation:
It is possible to sum enthalpies of half-reactions to obtain the enthalpy of a global reaction using Hess's law. For the reactions:
1) H₂(g) + ¹/₂O₂(g) ⟶ H₂O(g) ΔH₁= −241.8 kJ
2) X(s) + 2Cl₂(g) ⟶ XCl₄(s) ΔH₂= +361.7 kJ
3) ¹/₂H₂(g) + ¹/₂Cl₂(g) ⟶ HCl (g) ΔH₃= −92.3 kJ
4) X(s) + O₂(g) ⟶ XO₂(s) ΔH₄= − 607.9 kJ
5) H₂O(g) ⟶ H₂O(l) ΔH₅= − 44.0 kJ
The sum of (4) - (2) produce:
6) XCl₄(s) + O₂(g) ⟶ XO₂(s) + 2Cl₂(g) ΔH₆ = ΔH₄ - ΔH₂ = -969,6 kJ
(6) + 4×(3):
7) XCl₄(s) + 2H₂(g) + O₂(g) ⟶ XO₂(s) + 4HCl(g) ΔH₇ = ΔH₆ + 4ΔH₃= -1338,8 kJ
(7) - 2×(1):
8) XCl₄(s) + 2H₂O(g) ⟶ XO₂(s) + 4HCl(g) ΔH₈ = ΔH₇ - 2ΔH₁= -855,2kJ
(8) - 2×(5):
9) XCl₄(s) + 2H₂O(l) ⟶ XO₂(s) + 4HCl(g) ΔH₉ = ΔH₈ - 2ΔH₅= <em>-767,2kJ</em>
I hope it helps!
Answer:
8000 metres is equal to 4.971 miles
equation
8000 (number of meters) divided by 1609.34 ( equivalent of miles in one meter)
is equal to 4.971
Bases are iconic compounds that produce negative hydroxide ions (OH-) when dissolved in water. Bases taste bitter, feel slippery, and conduct electricity when dissolved in water.... Bases turn red litmus paper blue. The strength of bases is measured on the pH scale.
Answer:
None of these are correct, because there is no way to balance this equation, but I hope these steps help you figure out your answer.
Explanation:
Count out the single amounts of elements you have on both sides of the equation. To be balanced, you need to have the exact same for each element.
Before balanced Left side.
Cl-2
O-8
H-2
Before balanced right side.
H-1
Cl-1
O-3
That means we need to increase Hydrogen, Chlorine and Oxygen on the right for sure and see how that affects the equation. You can keep adding the Coefficients until the # of elements begin to match on each side.
(I tried to balance this equation, it doesn't work, there is too much on the reactants side for what the product is.)
