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2 years ago

Question 3 of 25

1 answer:

Colt1911 [192]2 years ago

8 0

The statement that describes a question that can guide the design of a scientific investigation could be about the necessity of a controlled variable. The correct answer is A.

<h3>What is a controlled variable?</h3>

It is a variable whose values are controlled by the researcher during the course of experimental investigations.

When designing an experiment, it is necessary to identify the different variables that would be involved for a successful investigation.

Variables can be independent, dependent, controlled, or constant. Identifying the necessary variables will help in designing the experiment.

More on variables can be found here: brainly.com/question/15740935

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Looking at the periodic table, which of these elements has the smallest atomic radius?

Triss [41]

Flourine I guess must be the answer

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3 years ago

Zinc reacts with hydrochloric acid according to the reaction equation Zn ( s ) + 2 HCl ( aq ) ⟶ ZnCl 2 ( aq ) + H 2 ( g ) How ma

Katen [24]

Answer: 12.0 milliliters of 6.50 M HCl ( aq ) are required to react with 2.55 g Zn.

Explanation:

moles = $\frac{\text {given mass}}{\text {Molar mass}}$

moles of zinc = $\frac{2.55g}{65.38g/mol}=0.0390moles$

The balanced chemical equation is :

$Zn(s)+2HCl(aq)\rightarrow ZnCl_2(aq)+H_2(g)$

According to stoichiometry:

1 mole of zinc reacts with = 2 moles of HCl

Thus 0.0390 moles of zinc reacts with = $\frac{2}{1}\times 0.0390=0.0780$ moles of HCl

To calculate the volume for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution in ml}}$ .....(1)

Molarity of $HCl$ solution = 6.50 M

Volume of solution = ?

Putting values in equation 1, we get:

$6.50M=\frac{0.0780\times 1000}{\text{Volume of solution in ml}}$

${\text{Volume of solution in ml}}=12.0ml$

Thus 12.0 ml of 6.50 M HCl ( aq ) are required to react with 2.55 g Zn

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3 years ago

1. What are some similarities between the dogs pictured? What are some differences?

kogti [31]

1. Some differences are that they are all different kinds of dogs

2. Small dogs and big dogs

That is all I can answer

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3 years ago

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I just need help with 2 chemistry questions! Can you please help me? I will give brainliest answer!

telo118 [61]

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3 years ago

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What is the mole-to-mole ratio between N2 and H2?

spin [16.1K]

Remember, look at the coefficients in the balanced equation! Here are three mole ratios:
1 mole<span> N2 / </span>3 moles<span> H2.</span>
3 moles<span> H2 / 2 moles NH3.
</span>

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3 years ago