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2 years ago

Evidence of a chemical change does NOT include

Chemistry

2 answers:

Elena-2011 [213]2 years ago

4 0

C. change in shape is the right answer

horrorfan [7]2 years ago

3 0

C is the correct answer for this question. since it is a physical change

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A 60g sample of tetraethyl lead, a gasoline additive, is found to contain 38.43g lead, 17.83g carbon and 3.74g hydrogen. Determi

anastassius [24]

Answer:

Empirical formula (which matches the molecular formula) is = PbC₈H₂₀

Explanation:

Our sample: 60 g of tetraethyl lead

In order to determine the compound empirical formula we need the centesimal composition:

(Mass of element / Total mass) . 100 =

(38.43 g lead / 60g ) . 100 = 64.05%

(17.83 g C / 60g) . 100 = 29.72%

(3.74 g H / 60g) . 100 = 6.23 %

These % are the mass of the elements in 100 g of compound. Let's find out the moles of them:

64.05 g / 207.2 g/mol = 0.309 moles

29.72 g / 12 g/mol = 2.48 moles

6.23 g/ 1 g/mol = 6.23 moles

Next, we divide the moles, by the lowest value of them (0.309)

0.309 / 0.309 = 1 mol Pb

2.48 / 0.309 = 8 mol C

6.23 / 0.309 = 20 mol H

There, we have our formula PbC₈H₂₀

6 0

3 years ago

Please Help 3. Were there any metallic compounds that did not react with either the acid or the base? Write the type of metal, b

Norma-Jean [14]

Answer:

1)KNO3 ( pottasium trioxonitrate (V)

2)Ca(NO3)2 (calcium trioxonitrate (V

Explanation:

1)KNO3 ( pottasium trioxonitrate (V)

2)Ca(NO3)2 (calcium trioxonitrate (V)

Thses two compounds are metallic compounds and does not react with either the acid or the base.

Write the type of metal, based on your examination of the periodic table?

1)KNO3 ( pottasium trioxonitrate (V) have a potassium element which belongs to group 2 of the Periodic table which is an alkaline metal and can react with water or steàm

2)Ca(NO3)2 (calcium trioxonitrate (V) has calcium metal element which is an alkaline earth metal in the Periodic table and they react with Hallogens

5 0

2 years ago

SUPPER EASY WILL GIVE BRAINLIEST NEED HELP ASAP

emmainna [20.7K]

Answer:

Your answer will be (D).

Hope this helps!

7 0

2 years ago

Read 2 more answers

Which is a common way for a scientific calculator to show the number below? <br> 8.1 102

Elodia [21]

Answer: 8.1e+2 or 8.1E+2 (in the scientific notation mode), based on that the number given is 8.1 × 10².

Explanation

Scientific calculators use the letter e or E to show the numbers in scientific notation mode.

These are some examples of numbers that require scientific notation and how they are shown.

Number                 Scientific calculator display

6.022 × 10²³           6.022 e+23
5 × 10 -12              5 E -12

So, understanding that your question is about number 8.1 × 10², the scientific calculator could show 8e+2.

Nevertheless, since 8 .1 × 10² is 810, not a long number, if the display is not in scientific notation mode, it could just display just 810,

7 0

3 years ago

The standard cell potential Ec for the reduction of silver ions with elemental copper is 0.46V at 25 degrees celsius. calculate

Cloud [144]

Answer : The $\Delta G$ for this reaction is, -88780 J/mole.

Solution :

The balanced cell reaction will be,

$Cu(s)+2Ag^+(aq)\rightarrow Cu^{2+}(aq)+2Ag(s)$

Here, magnesium (Cu) undergoes oxidation by loss of electrons, thus act as anode. silver (Ag) undergoes reduction by gain of electrons and thus act as cathode.

The half oxidation-reduction reaction will be :

Oxidation : $Cu\rightarrow Cu^{2+}+2e^-$