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4 years ago

Which indicator most likely suggests that a chemical change is taking place?

Chemistry

2 answers:

Jlenok [28]4 years ago

7 0

I say change in color and state

Nezavi [6.7K]4 years ago

5 0

Chemical change is most often indicated by a change in color.

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Draw four possible Lewis structures of the molecule xenon trioxide, XeO3, one each with zero, one, two, or three Xe−O double bon

algol [13]

Answer:

See the image below

Explanation:

To draw a Lewis structure of a molecule, you place the least electronegative atom (Xe) as the central atom, with the more electronegative atoms (O) surrounding it.

Then you distribute the electrons around the atoms, giving every one an octet and placing any extra electrons on the central atom.

This procedure gives you four possible Lewis structures, so the actual structure is a resonance hybrid of them all.

Structure D has no formal charges, so it is the major contributor.

7 0

3 years ago

Trichloroethylene, a widely used degreasing solvent for machine parts, is produced in a two-step reaction sequence. Ethylene is

solmaris [256]

Answer:

ΔH°C2H2Cl4(l) = -333,36 kJ/mol

ΔH°r₂ = -35,14 kJ/mol

Explanation:

The ΔH°r of the first reaction is:

ΔH°r = -385,76 kJ/mol = (ΔH°C2H2Cl4(l) + ΔH°H2(g)) - (ΔH°C2H4(g) + 2ΔHCl2 (g))

ΔH°H2(g) = 0 kJ/mol

ΔH°C2H4(g) = 52,4 kJ/mol

Δ°HCl2 (g) = 0 kJ/mol

Replacing:

ΔH°C2H2Cl4(l) = -385,76 kJ/mol + 52,4 kJ/mol = -333,36 kJ/mol

The standard heat of the second reaction is:

ΔH°r₂ = ΔH°C2HCl3(l) + ΔH°HCl(g) - ΔH°C2H2Cl4(l)

Where:

ΔH°C2HCl3(l) = -276,2 kJ/mol; ΔH°HCl(g) = -92,3 kJ/mol; ΔH°C2H2Cl4(l) = -333,36 kJ/mol

Replacing:

ΔH°r₂ = -276,2 kJ/mol -92,3 kJ/mol + 333,36 kJ/mol

ΔH°r₂ = -35,14 kJ/mol

I hope it helps!

4 0

3 years ago

Determine if the following compounds are likely to have ionic or covalent bonds. a. Magnesium oxide (MgO) _______________ b. Str

nika2105 [10]

Answer:

The answer to your question is below

Explanation:

Ionic bond is a kind of bond in which a metal attaches to a nonmetal. Also we know that a molecule has ionic bonding if the electronegativity is higher than 1.7.

Kind of elements Difference of electronegativity Bond

a) MgO Metal - Nonmetal 3.44 - 1.31 = 2.13 Ionic

b) SrCl₂ Metal -Nonmetal 3.16 - 0.95 = 2.21 Ionic

c) O₃ Nonmetal- Nonmetal 3.44 - 3.44 = 0 Covalent

d) CH₄O Nonmetal-Nonmetal 3.44 - 2.55 = 0.89 Covalent

Carbon, Hydrogen and oxygen are nonmetals

2) Silver coins can conduct electricity.

4 0

3 years ago

All changes saved

Kipish [7]

Answer:

4.00L

Explanation:

Using Charle's law, which have the following equation:

V1/T1 = V2/T2

Where;

V1 = initial volume (litres)

T1 = initial temperature (Kelvin)

V2 = final volume (litres)

T2 = final temperature (Kelvin)

According to the information provided, T1 = 275K, T2 = 400K, V1 = ?, V2 = 5.82L

Hence, using the formula;

V1/275 = 5.82/400

400 × V1 = 275 × 5.82

400V1 = 1600.5

V1 = 1600.5 ÷ 400

V1 = 4.001

Therefore, volume of the gas before it is heated is 4.00L

4 0

3 years ago

A sample of ammonia is found to occupy 0.250 L under laboratory conditions of 27 °C and 0.850 atm. Find the volume of this sampl

Rzqust [24]

Answer:

0.193 L

Explanation:

Step 1:

Data obtained from the question.

Initial Volume (V1) = 0.250 L

Initial temperature (T1) = 27°C

Initial pressure (P1) = 0.850 atm

Final volume (V2) =?

Final temperature (T2) = 0°C

Final pressure (P2) = 1.00 atm

Step 2:

Conversion of celsius temperature to Kelvin temperature.

Temperature (Kelvin) = temperature (celsius) + 273

Initial temperature (T1) = 27°C = 27°C + 273 = 300K

Final temperature (T2) = 0°C = 0°C + 273 = 273K

Step 3:

Determination of the new volume of the sample of ammonia gas.

The new volume can be obtain by using the general gas equation as shown below:

P1V1/T1 = P2V2/T2

0.850x0.250/300 = 1xV2/273

Cross multiply to express in linear form

300 x V2 = 0.850x0.250x273

Divide both side by 300

V2 = (0.850x0.250x273) /300

V2 = 0.193 L

Therefore, the volume of the sample at 0 °C and 1.00 atm is 0.193 L

6 0

3 years ago