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SSSSS [86.1K]
3 years ago
13

Evan was in his bedroom when he heard the sound of breaking glass. He went out to the kitchen to see a vase broken on the floor

and his dog walking away. Evan said "the dog broke the vase!” This statement is an
A. observation because he knows that his dog broke the vase.
B. observation because he heard the vase break before he came into the room.
C. inference because he formed a logical conclusion based on the evidence.
D. inference because he is blaming the dog without any proof.
Chemistry
2 answers:
emmainna [20.7K]3 years ago
7 0
The answer is d because he did not see the dog do it
Anna11 [10]3 years ago
3 0

Answer:D. inference because he is blaming the dog without any proof.

Explanation:

Observation can be define as a process of monitoring something by visual examination. Inference is a concluding content which is based on the observation and prior knowledge of the concept.

The given statement is the inference which is only based on the observation and there is no definite proof that the dog has actually broken the vase.

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NARA [144]
It is number 1. CaBr2
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3 years ago
Two forces are acting on a wheelbarrow.One force is pushing to the right and an equal force is pushing to the left.What can you
andreev551 [17]
B. It is not accelerating since equal and opposite forces cancel each other. Hope it helps
7 0
4 years ago
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A 1.00 g sample of a metal X (that is known to form X ions in solution) was added to 127.9 mL of 0.5000 M sulfuric acid. After a
Semenov [28]

<u>Answer:</u> The metal having molar mass equal to 26.95 g/mol is Aluminium

<u>Explanation:</u>

  • To calculate the number of moles for given molarity, we use the equation:

\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}     .....(1)

Molarity of NaOH solution = 0.5000 M

Volume of solution = 0.03340 L

Putting values in equation 1, we get:

0.5000M=\frac{\text{Moles of NaOH}}{0.03340L}\\\\\text{Moles of NaOH}=(0.5000mol/L\times 0.03340L)=0.01670mol

  • The chemical equation for the reaction of NaOH and sulfuric acid follows:

2NaOH+H_2SO_4\rightarrow Na_2SO_4+H_2O

By Stoichiometry of the reaction:

2 moles of NaOH reacts with 1 mole of sulfuric acid

So, 0.01670 moles of NaOH will react with = \frac{1}{2}\times 0.01670=0.00835mol of sulfuric acid

Excess moles of sulfuric acid = 0.00835 moles

  • Calculating the moles of sulfuric acid by using equation 1, we get:

Molarity of sulfuric acid solution = 0.5000 M

Volume of solution = 127.9 mL = 0.1279 L    (Conversion factor:  1 L = 1000 mL)

Putting values in equation 1, we get:

0.5000M=\frac{\text{Moles of }H_2SO_4}{0.1279L}\\\\\text{Moles of }H_2SO_4=(0.5000mol/L\times 0.1279L)=0.06395mol

Number of moles of sulfuric acid reacted = 0.06395 - 0.00835 = 0.0556 moles

  • The chemical equation for the reaction of metal (forming M^{3+} ion) and sulfuric acid follows:

2X+3H_2SO_4\rightarrow X_2(SO_4)_3+3H_2

By Stoichiometry of the reaction:

3 moles of sulfuric acid reacts with 2 moles of metal

So, 0.0556 moles of sulfuric acid will react with = \frac{2}{3}\times 0.0556=0.0371mol of metal

  • To calculate the molar mass of metal for given number of moles, we use the equation:

\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}

Mass of metal = 1.00 g

Moles of metal = 0.0371 moles

Putting values in above equation, we get:

0.0371mol=\frac{1.00g}{\text{Molar mass of metal}}\\\\\text{Molar mass of metal}=\frac{1.00g}{0.0371mol}=26.95g/mol

Hence, the metal having molar mass equal to 26.95 g/mol is Aluminium

6 0
3 years ago
This question is about iron three of the raw material added to a blast furnace used to extract iron from henatite are coke hemat
IrinaVladis [17]

Answer: The fourth material that is added to the blast furnace is HOT AIR which provides OXYGEN for used for combustion of carbon (Coke).

Explanation:

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Iron can be extracted from its ore with the used of blast furnace. The materials used for extraction of iron includes:

--> Coke

--> haematite( iron ore)

--> limestone and

--> Hot air.

The iron ore is first roasted in air so that iron(III)oxide is produced. The iron(III)oxide is then mixed with coke and limestone and heated to a very high temperature. Hot air is introduced into it from the bottom of the furnace. The coke is oxidizes the the oxygen in the hot air blast to liberate carbondioxide.

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viktelen [127]

Answer:

ok will do

Explanation:

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