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2 years ago

In an experiment, what is the purpose of the control group?

2 answers:

7 0

A control group is the comparison group that helps to "make sure your experiment works." A control group is separated from the rest of the experiment and nothing happens to it kinda like a controlled variable. Controlled variables are the variables in a experiment that remains the same for example a temperature, time, type of products, etc..

Hope this helps!

goldenfox [79]2 years ago

3 0

In an experiement, the purpose of a control group is to make sure the experiment that your working on works!

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Does SiF4 have polar covalent bonds?

Kamila [148]

Answer:

SiF4 is not a polar covalent bond.

Explanation:

SiF4 is a nonpolar molecule because the fluorine's are arranged around the central silicon atom in a tetrahedral molecule with all of the regions of negative charge cancelling each other out.

8 0

2 years ago

Calculate the pH and fraction of dissociation ( α ) for each of the acetic acid ( CH 3 COOH , p K a = 4.756 ) solutions. A 0.002

marysya [2.9K]

Answer:

The degree of dissociation of acetic acid is 0.08448.

The pH of the solution is 3.72.

Explanation:

The $pK_a=4.756$

The value of the dissociation constant = $K_a$

$pK_a=-\log[K_a]$

$K_a=10^{-4.756}=1.754\times 10^{-5}$

Initial concentration of the acetic acid = [HAc] =c = 0.00225

Degree of dissociation = α

$HAc\rightleftharpoons H^++Ac^-$

Initially

At equilibrium ;

(c-cα) cα cα

The expression of dissociation constant is given as:

$K_a=\frac{[H^+][Ac^-]}{[HAc]}$

$1.754\times 10^{-5}=\frac{c\times \alpha \times c\times \alpha}{(c-c\alpha)}$

$1.754\times 10^{-5}=\frac{c\alpha ^2}{(1-\alpha)}$

$1.754\times 10^{-5}=\frac{0.00225 \alpha ^2}{(1-\alpha)}$

Solving for α:

α = 0.08448

The degree of dissociation of acetic acid is 0.08448.

$[H^+]=c\alpha = 0.00225M\times 0.08448=0.0001901 M$

The pH of the solution ;

$pH=-\log[H^+]$

$=-\log[0.0001901 M]=3.72$

3 0

3 years ago

What is the original source of most energy used on Earth?

ser-zykov [4K]

Answer:

the sun Solar energy

Explanation:

Energy from the sun. Solar energy is the original source of most energy on Earth. There are many ways we use energy from the Sun.

3 0

2 years ago

Read 2 more answers

For the reaction shown, calculate how many moles of NO2 form when each amount of reactant completely reacts.

Anton [14]

Answer:- 2.4 mol $NO_2$ .

Solution:- It asks to calculate the moles of $NO_2$ formed when 1.2 moles of $N_2O_5$ are reacted.

There is 2:4 mol ratio between $N_2O_5$ and $NO_2$ . So, the moles of reactant are multiplied by the mol ratio to get the moles of $NO_2$ . The calculations are shown below:

$1.2mol N_2O_5(\frac{4mol NO_2}{2mol N_2O_5})$

= 2.4 mol $NO_2$

So, 2.4 moles of $NO_2$ are formed when 1.2 moles of $N_2O_5$ were reacted.

7 0

2 years ago

Read 2 more answers

The process that splits rock through freezing and thawing is called?

maw [93]

It's called Ice Wedging :)

8 0

3 years ago