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Tanya [424]
3 years ago
15

Are changes in the state of matter (phase) considered physical or chemical changes? Why?

Chemistry
1 answer:
Flauer [41]3 years ago
3 0

Answer:

Physical changes

Explanation:

Changes in the state of matter are physical changes.

First, the material is made up of the same components that is was before it changed states.

The physical properties of the material changed, but its chemical composition did not, meaning that is is a physical change.

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The standard enthalpy of formation for glucose [c6h12o6(s)] is −1273.3 kj/mol. what is the correct formation equation correspond
balu736 [363]
The standard formation equation for glucose C6H12O6(s) that corresponds to the standard enthalpy of formation or enthalpy change ΔH°f = -1273.3 kJ/mol is 
     C(s) + H2(g) + O2(g) → C6H12O6(s)
and the balanced chemical equation is 
     6C(s) + 6H2(g) + 3O2(g) → C6H12O6(s)

Using the equation for the standard enthalpy change of formation 
     ΔHoreaction = ∑ΔHof(products)−∑ΔHof(Reactants)
     ΔHoreaction = ΔHfo[C6H12O6(s)] - {ΔHfo[C(s, graphite) + ΔHfo[H2(g)] + ΔHfo[O2(g)]}

C(s), H2(g), and O2(g) each have a standard enthalpy of formation equal to 0 since they are in their most stable forms:
     ΔHoreaction = [1*-1273.3] - [(6*0) + (6*0) + (3*0)]
                           = -1273.3 - (0 + 0 + 0)
                           = -1273.3
8 0
3 years ago
1. What is an isomer? How many possible isomers of hexane are there? What are the structural differences between these isomers?
VARVARA [1.3K]
Answer 1:
Isomers are compounds with same molecular formula but different structure formula. Isomers are classified into two types
a) Structural/configurational isomers
b) Stereo isomers
In structural/configurational isomers  atom and functional groups are attached in different fashion. Structural isomers may have different functional groups. Structural isomers are further classified as chain isomers, position isomers and functional isomers. In case of stereo-isomers, compounds have same functional group, but different orientation in space. They also have difference activity towards polarized light.

 Answer 2:
Hexane has a molecular formula of C6H14. It exhibits following structural isomers
a) hexane<span>,
b) 2-methylpentane
c)3-methylpentane
d) 2,2-dimethylbutane
e) 2,3-dimethylbutane
Thus, in all there are 5 isomers of hexane

Answer 3: 
</span><span>Butane has two possible isomers but that decane has 75 possible isomers. This can be attributed to the fact that butane has 4 carbon atoms, while decane has 10 carbon atom. As the number of carbon atom increases, there are higher possible sites of linkage, in different fashion. Therefore, as number 69 of carbon atoms increases, number of different possible isomers increases. 

Answer 4:
It has been observed that, though isomers have same molecular formula, but the have different boiling points. Infact, branched isomers have lower boiling point as compared to linear isomers. For example, hexane has boiling point = 69 oC, 2 methyl pentane has boiling point = 60 oC, 2,4, dimethyl butane has boiling point = 58 oC and 2,2 dimethyl butane has boiling point = 50 oC. Thus, it can be observed that branched isomers have lower boiling points as compared to linear isomers. This can be attributed to lower van der Waal's forces of interaction in branched isomers as compared to linear isomers. 
</span><span>
</span>
5 0
2 years ago
An ion has a mass number of 65, 36 neutrons, and a charge of +1 . Identify the element symbol, and determine the number of proto
docker41 [41]

Answer:

Element symbol Cu

Number of protons 29

Number of electrons 28

Explanation:

To get the element symbol, we need the name of the element. To correctly identify the name of the element, we need the proton number.

Now the mass number is 65 and the number of neutrons is 36. The number of protons is this the mass number minus the number of neutrons. This equals 65 - 36 = 29 protons.

The element with 29 protons is copper Cu.

Now to get the number of electrons, for an electrically neutral atom , the number of electrons equals the number of protons. But here, the atom is not electrically neutral anymore as it has now formed a univalent positive ion of +1.

To form a positive ion, you have to do so by losing electrons. The atom in question here has just lost one electron. Thus, our of the 29, it is left with only 28 electrons.

8 0
3 years ago
Read 2 more answers
Complete this neutralization equation:<br> H2SO4 + Al(OH)3
elena-s [515]

Answer:

H2SO4 + Al(OH)3 = Al2(SO4)3 + H2O

Explanation:

4 0
3 years ago
What is it called when moon is between setting and rising
miv72 [106K]

Answer:

I hope this link helps you.

Explanation:

http://astronomy.swin.edu.au/cosmos/P/Phases

4 0
3 years ago
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