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aleksandrvk [35]
3 years ago
15

Which are geologic evidence?​

Chemistry
1 answer:
Naya [18.7K]3 years ago
6 0
The scientific study of the origin, history, structure, and composition of the earth.
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Which of the following is and example of a chemical change
givi [52]
Hi! where are the options?
6 0
3 years ago
A solution contains some or all of the ions Cu2+,Al3+, K+,Ca2+, Ba2+,Pb2+, and NH4+. The following tests were performed, in orde
xeze [42]

Answer:

See below explanation

Explanation:

When having a mixture of metals in solution, you may perform an analytical study (using selective chemical conditions), that may help you to determine whether a metal (cation) is present or not

Using selective analytes (or conditions), leads to consecutive precipitations, until most of the cations are separated in precipitates

With this technique, you may identify metals in different groups, each group will have its analyte (or condition), which will help to have a different precipitate:

- Group I: Ag⁺, Pb⁺², Hg⁺²;  Analyte: HCL ; Precipitate: AgCl (white) , PbCl₂, HgCl₂

- Group II: As⁺³ , Bi⁺³, Cd⁺², Cu⁺² , Sb⁺³, Sn⁺² ; Analyte: H₂S (g) with HCL ; Precipitate: As₂S₃ , Bi₂S₃ , CdS (yellow) , CuS (black), Sb₂S₃, SnS

- Group III: Co⁺², Fe⁺², Fe⁺³, Mn⁺², Ni⁺², Zn⁺², Al⁺³, Cr⁺³; Analyte: NaOH or NH₃ with (NH₄)₂S (ac) ; Precipitate: CoS (black) , FeS, MnS , NiS (black), ZnS (white) , Al(OH)₃ (white), Cr(OH)₃  

- Group IV: Mg⁺², Ca⁺², Sr⁺², Ba⁺²; Analyte: Na₂CO₃ (ac) or (NH₄)₂HPO₄ (ac); Precipitate: respective carbonate or phosphate MgCO₃/MgHPO₄, CaCO₃/CaHPO₄ , SrCO₃/SrHPO₄, BaCO₃/BaHPO₄

- Group V: Li⁺, K⁺, Na⁺, Rb⁺, Cs⁺, NH₄⁺ ; will remain all in final solution

According to the original statement:

A solution contains one or more of the following: Cu⁺², Al⁺³, K⁺, Ca⁺², Ba⁺², Pb⁺², NH₄⁺

1) Addition on HCl 6M produces no change: we can say the sample does not contain Pb⁺² (group I)

2) Addition of H₂S with 0.2 M HCL produced a black solid: we could say sample contains Cu⁺²(group II)

3) Addition of (NH₄)₂HPO₄ in NH₃ produces no reaction: we could say we don´t have Ca⁺² and /or Ba⁺²  (group IV)

4) The final supernatant, when heated produced a purple flame: in the final solution, we have K⁺ (group V), which produces a purple flame (based on its characteristic emission spectrum when subjected to flame)

This analysis will be inconclusive for NH₄⁺ (according to above describe technique)

6 0
3 years ago
Sevin, the commercial name for an insecticide used to protect crops such as cotton, vegetables, and fruit, is made from carbamic
xeze [42]

Answer:

Explanation:

Ratio of mass of C , N , H and O

= .8007 :0.9333:0.2016:2.133

Ratio of moles of C , N , H and O

= .8007/12 : .9333 / 14 : 0.2016 / 1 : 2.133/16

= .0667 : .0667: .2016 : .1333

= .0667 / .0667 : .0667 / .0667 : .2016 /.0667 : .1333 / .0667

= 1 : 1 : 3: 2

Hence empirical formula = CNH₃O₂

7 .

Weight of titanium Ti = 1.916 g

Weight of oxygen = 3.196 - 1.916 = 1.28 g

Ratio of weight of Ti and O

= 1.916 : 1.28

Ratio of moles  of Ti and O

1.916/48 : 1.28/16  [ Molecular  weight of Titanium is 48 ]

= .04 : .08

= .04/.04 : .08/.04

= 1 :2 .

Empirical formula

TiO₂

5 0
2 years ago
9. A gas canister can tolerate internal pressures up to 210 atmospheres. If a 2.0 L
Reika [66]

:))))))))

Here is my Answer:

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mario62 [17]
I say both equinox because winter solstice has the least amount of sunlight and the summer solstice has the most ampunt of daylight so i said both equinox
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3 years ago
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