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
Answer: The statement that is not a determining factor in formation of intrusive igneous rocks is 'None of the above' and Magma cools very fast beneath the Earth's surface.
Explanation:
Rocks are naturally occurring solid materials that are made up of different types of minerals which affects it's texture and colours. The three main types of rocks are:
--> sedimentary rocks,
--> metamorphic rocks and
--> igneous rocks.
Igneous rocks are formed from the crystallization and solidification of hot molten rocks which originates from deep within the earth. Depending on where the molten rock solidifies, the igneous rock is divided into two, namely:
--> intrusive igneous rock and
--> extrusive igneous rock.
The INTRUSIVE IGNEOUS rocks are formed within or deep beneath the earth surface when the hot magma SLOWLY cools over millions of years until it solidifies. The slow cooling allows large crystals to grow.
Therefore the statements (None of the above and Magma cools very fast beneath the Earth's surface) are not a determining factor.
To determine the empirical formula of the compound given, we need to determine the ratio of each element in the compound. An empirical formula is a formula that gives the proportions of the elements present in a certain compound however it does not give the actual numbers or the arrangement of the atoms.The empirical formula of the ionic compounds that could be formed from the given ions are calcium bromide (CaBr2), calcium sulfide (CaS), Lead Bromide (PbBr4) and Lead sulfide (Pb2S4).
A square mile = 27,878,400 square feet
A square mile also = 640 acres.
31,580/.75 = 43,440 persons per square mile
That is 27,878,400/43,440 = ~642 square feet per person so each person has a square approximately 25 feet on each side.
43440/640 = ~ 68 people per acre
This is a fairly dense
