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mr_godi [17]
3 years ago
10

Humans have used rocks in the creation of tools and building materials true or flase

Chemistry
2 answers:
olga55 [171]3 years ago
8 0

Answer:

true

Explanation:

Anuta_ua [19.1K]3 years ago
4 0
True, if you would like an example look at Indian arrow heads or early architecture all use rocks.
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A propane stove burned 470 grams propane and produced 625 grams of water (this is the actual yield) C3H8 +5O2=3CO2+4H20. What wa
Liula [17]

Answer:

81.3%

Explanation:

Step 1:

The balanced equation for the reaction:

This is shown below:

C3H8 + 5O2 —> 3CO2 + 4H2O

Step 2:

Data obtained from the question. This includes:

Mass of propane (C3H8) = 470 g

Actual yield of water (H2O) = 625 g

Percentage yield of water (H2O) =?

Step 3:

Determination of the mass of propane (C3H8) burned and the mass of water (H2O) produce from the balanced equation. This is illustrated below:

C3H8 + 5O2 —> 3CO2 + 4H2O

Molar Mass of C3H8 = (3x12) + (8x1) = 36 + 8 = 44g/mol

Molar Mass of H2O = (2x1) + 16 = 2 + 16 = 18g/mol

Mass of H2O from the balanced equation = 4 x 18 = 72g

From the balanced equation above,

44g of C3H8 was burned and 72g of H2O was produced.

Step 4:

Determination of the theoretical yield of H2O. This is illustrated below:

From the balanced equation above,

44g of C3H8 produced 72g of H2O.

Therefore, 470g of C3H8 will produce = (470x72)/44 = 769.09g of H2O.

Therefore, the theoretical yield of H2O is 769.09g

Step 5:

Determination of the percentage yield of water (H2O). This is illustrated below:

Actual yield of water (H2O) = 625g

theoretical yield of H2O = 769.09g

Percentage yield of water (H2O) =?

Percentage yield = Actual yield/Theoretical yield x100

Percentage yield = 625/769.09 x100

Percentage yield = 81.3%

Therefore, the percentage yield of water (H2O) is 81.3%

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3 years ago
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Legumes are much easier to grow than other plants, and are more adaptable.

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The flow of stimuli information in the body is from the receptors to sensory neuron (afferent neurons) to the interneurons then to the central nervous system (brain and spinal cord) then is carried of by the motor neurons (efferent neurons) to the mucles involve.

Sensation to transduction to perception. Sensation is the ambiguous information which is received by the receptors or sensory organ henceforth, transduction occurs in the nerve cell protruding to the brain and is now called perception as the vague stimuli is interpreted and processed to be understood then is responded with the proper and apt response or reaction.

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All the following are signs of a chemical reaction, except
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C. a change of state. It can be a physical or a chemical state of change.
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im gonna get a warning watch

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