Answer:
Extinction event or sometimes known as Mass extinction
Explanation:
These events typically are typically widespread and rapid decrease in the biodiversity (which takes into account spread and existence of current species). The worst mass extinction was Permian–Triassic extinction where over 90% of species of organisms vanished.
Answer: 2. magnesium
Explanation: correct spelling...?
<em>Five household items that </em><em>contain</em><em> the same chemicals as cigarettes :</em><em>-</em>
- <em>Perfume</em>
- <em>Household</em><em> </em><em>cleaning</em><em> </em><em>products</em>
- <em>Beauty</em><em> </em><em>Products</em>
- <em>Sunscreen</em>
- <em>Water</em><em> </em><em>bottles</em>
<em>They</em><em> </em><em>contain</em><em> </em><em>toxic</em><em> </em><em>substances</em><em>!</em>
<em>hope</em><em> </em><em>it</em><em> </em><em>helps</em><em>!</em>
A colloid has the particles that have the ability to scatter light called the Tyndall effect named after the scientist named Tyndall. A suspension has large suspended particles that settle out at the bottom of the container. A solution has small particles that are evenly distributed throughout. Hence the answer is choice 2.
Correct Question:
A chemist measures the enthalpy change ΔH during the following reaction: Fe(s) + 2HCl(g)-->FeCl2(s) + H2 ΔH=-157.0 kJ. Use this information to complete the table below. Round each of your answers to the nearest kJ/mol
Answer:
-314 kJ
+628 kJ
+157 kJ
Explanation:
The enthalpy change of a reaction measures the amount of heat that is lost or gained by it. If ΔH >0 the heat is gained, and the reaction is called endothermic, if ΔH<0, the heat is lost, and the reaction is called exothermic.
If the reaction is inverted, the value of ΔH is inverted too (the opposite endothermic reaction is exothermic), and if the reaction is multiplied by a constant, ΔH will be multiplied by it too.
1) 2Fe(s) + 4HCl --> 2FeCl2(s) + 2H2(g)
This reaction is the product of the given reaction by 2, so
ΔH = 2*(-157) = -314 kJ
2) 4FeCl2(s) + 4H2(g) --> 4Fe(s) + 8HCl(g)
This reaction is the inverted reaction given multiplied by 4, so
ΔH = 4*(157) = +628 kJ
3) FeCl2(s) + H2(g) --> Fe(s) + 2HCl
This reaction is the inverted reaction given, so
ΔH = +157 kJ
