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Gelneren [198K]

3 years ago

15

what do the colors produced by fireworks indicate? a. a physical change c. a state change b. a chemical change d. an element cha

nge

1 answer:

Nat2105 [25]3 years ago

6 0

B. A chemical change

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In a test of an automobile engine 1.00 L of octane (702 g) is burned, but only 1.84 kg of carbon dioxide is produced. What is th

Reptile [31]

Answer:

The % yield of CO2 is 85.05 %

Explanation:

Step 1: Data given

Mass of octane = 702 grams

Molar mass octane = 114.23 g/mol

Mass CO2 =1.84 kg = 1840 grams

Molar mass of CO2

Step 2: The balanced equation

2C8H18 + 25O2 → 16CO2 + 18H2O

Step 3: Calculate moles of octane

Moles octane = mass octane / molar mass octane

Moles octane = 702.0 grams / 114.23 g/mol

Moles octane = 6.145 moles

Step 4: Calculate moles of CO2

For 2 moles octane we need 25 moles O2 to produce 16 moles CO2 and 18 moles H2O

For 6.145 moles octane we'll have 8*6.145 moles =49.16 moles

Step 5: Calculate mass of CO2

Mass CO2 = moles CO2 * molar mass CO2

Mass CO2 = 49.16 moles * 44.01 g/mol

Mass CO2 = 2163.5 grams

Step 6: Calculate % yield of carbon dioxide

% yield = (actual yield / theoretical yield)*100%

% yield = (1840/2163.5)*100%

% yield = 85.05 %

The % yield of CO2 is 85.05 %

4 0

3 years ago

A chemist performs the same tests on two homogeneous white crystalline solids, A and B. The results are shown in the table below

Nookie1986 [14]

Solid A contains only Covalent bonds and solid B only contains Ionic bonds. I know this because the appearance, solubility, and conductivity of solid A describes Covalent bonds.

Explanation:

Try this, but idk if it will be marked as correct.

7 0

3 years ago

Write the proper word equation to express the following chemical reaction: 4Fe (s) + 3Sn(NO3)4 (aq) arrow 4Fe(NO3)3 (aq) + 3Sn (

Lapatulllka [165]

The word equation for this reaction is:

Iron + Tin nitrate → Iron nitrate + Tin

3 0

3 years ago

The process of ____ occurs when magma, lava, or a solute in a solution becomes a solid and the internal components will arrange

satela [25.4K]

Answer:

D. Crystallization

Explanation:

Let's clarify the irrelevant terms first.

unification: This term has nothing to do with chemistry at all
lithification: When the problem mentions magma and lava, you might think that this term is related to the process here. However, 'lithification' <em>do </em>have a precise meaning in geology. It refers to the process where sediments collapses into one single rock under pressure, which has nothing to do with the process mentioned here.

Now, for 2 terms that might confuse you: 'solidification' and 'crystallization' these also has precise scientific definition

Solidification is defined the process where substances in <em>liquid</em> phase changes its phase to <em>solid</em>. On first glance, this answer might seems correct, and yes, it is correct for this question. But not the <em>most</em> correct.

The keyword here is

'the internal components will arrange its self in an organized pattern.'

Crystallization is a special case of Solidification where the atoms or molecules of liquid solidify by spontaneously arrange themselves in periodic, ordered, and organized pattern. It might or might not happen during solidification depending on cooling rate, viscosity of liquid, and other factors.

So, Crystallization is the most correct answer here.

4 0

3 years ago

Is a octopus a carnivore or a herbivore

timofeeve [1]

Carnivore, but some are herbivores

4 0

3 years ago