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Snowcat [4.5K]
3 years ago
6

What are the indications/signs that a chemical change has occurred?

Chemistry
1 answer:
photoshop1234 [79]3 years ago
7 0
Light is given off, a permanent color change occurs, gas is given off, heat is given off, and a precipitate is formed<span />
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You are running a rather large scale reaction where you prepare the grignard reagent phenylmagnesium bromide by reacting 210.14
almond37 [142]

Answer:

We would expect to form 7.35 moles of grignard reagent.

Explanation:

<u>Step 1: </u>Data given

Mass of magnesium = 210.14 grams

Volume bromobenzene = 772 mL

Density of bromobenzene = 1.495 g/mL

Molar mass of Mg = 24.3 g/mol

Molar mass of bromobenzene = 157.01 g/mol

<u>Step 2</u>: The balanced equation

C6H5Br + Mg ⇒ C6H5MgBr

<u>Step 3:</u> Calculate mass of bromobenzene

Mass bromobenzene = density bromobenzene * volume

Mass bromobenzene = 1.495 g/mL * 772 mL

Mass bromobenzene = 1154.14 grams

<u>Step 4</u>: Calculate number of moles bromobenzene

Moles bromobenzene = mass bromobenzene / molar mass bromobenzene

Moles bromobenzene = 1154.14g / 157.01 g/mol

Moles bromobenzene = 7.35 moles

<u>Step 5:</u> Calculate moles of Mg

Moles Mg = 210.14 grams /24.3 g/mol

Moles Mg = 8.65 moles

<u>Step 6:</u> The limiting reactant

The mole ratio is 1:1 So the bromobenzene has the smallest amount of moles, so it's the limiting reactant. It will be completely consumed ( 7.35 moles). Magnesium is in excess, There will react 7.35 moles. There will remain 8.65 - 7.35 = 1.30 moles

<u>Step 7:</u> Calculate moles of phenylmagnesium bromide

For 1 mole of bromobenzene, we need 1 mole of Mg to produce 1 mole of phenylmagnesium bromide

For 7.35 moles bromobenzene, we have 7.35 moles phenylmagnesium bromide

We would expect to form 7.35 moles of grignard reagent.

5 0
3 years ago
If the copper ion just GAINED electrons,
viva [34]
Reduction is the answer
8 0
3 years ago
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In the following combustion reaction, what is the mole ratio of ethane (C2H6) to carbon dioxide? 2 C2H6 + 7 O2(g) 4 CO2 + 6 H2O
Gwar [14]
The answer you are looking four is 4/2 or 4CO2/2C2H6
4 0
3 years ago
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uysha [10]
C......…..……...............
5 0
3 years ago
Can you write the formula for and indicate the charge on each of the following ions: sodium ion, aluminum ion, chloride ion, nit
Anettt [7]
If the ion is named by (element-name) + ion, it is the element with a positive charge.
This means:
Sodium ion: Na(1+)
Aluminum ion: Al(3+)
If the ion is named by (element-prefix)+ide, then it has a negative charge.
This means:
Chloride: Cl(1-)
Nitride: N(3-)
Finally, if it has roman numerals after the name, that is the amount of positive charge the ion has.
Therefore:
Iron (II): Fe(2+)
Iron(III): Fe(3+)
8 0
3 years ago
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