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3 years ago

Why is it important to have a controlled experiment

2 answers:

6 0

It is important to have a control group in your experiment so you are able to compare your actual results to the control group

Alexus [3.1K]3 years ago

3 0

By the end of the day you know how much each group ate, abd you compare it with the control.In convlution,control is important because without it you'd have no way to understand the results after and experiment happens.

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Identify the unit cell that has a = B = y = 90°.

elixir [45]

Monoclinic I think. I'm not sure

8 0

3 years ago

Which particle builds a static electric charge when it is transferred from one object to another?

murzikaleks [220]

The answer would be, "Electrons".

3 0

3 years ago

How many grams of sodium acetate ( molar mass = 83.06 g/mol ) must be added to 1.00 Liter of a 0.200 M acetic acid solution to m

Pie

<u>Answer:</u> The mass of sodium acetate that must be added is 30.23 grams

<u>Explanation:</u>

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

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

Molarity of acetic acid solution = 0.200 M

Volume of solution = 1 L

Putting values in above equation, we get:

$0.200M=\frac{\text{Moles of acetic acid}}{1L}\\\\\text{Moles of acetic acid}=(0.200mol/L\times 1L)=0.200mol$

To calculate the pH of acidic buffer, we use the equation given by Henderson Hasselbalch:

$pH=pK_a+\log(\frac{[\text{salt}]}{[\text{acid}]})$

$pH=pK_a+\log(\frac{[CH_3COONa]}{[CH_3COOH]})$

We are given:

$pK_a$ = negative logarithm of acid dissociation constant of acetic acid = 4.74

$[CH_3COONa]=?mol$

$[CH_3COOH]=0.200mol$

pH = 5.00

Putting values in above equation, we get:

$5=4.74+\log(\frac{[CH_3COONa]}{0.200})$

$[CH_3COONa]=0.364mol$

To calculate the mass of sodium acetate for given number of moles, we use the equation:

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

Molar mass of sodium acetate = 83.06 g/mol

Moles of sodium acetate = 0.364 moles

Putting values in above equation, we get:

$0.364mol=\frac{\text{Mass of sodium acetate}}{83.06g/mol}\\\\\text{Mass of sodium acetate}=(0.364mol\times 83.06g/mol)=30.23g$

Hence, the mass of sodium acetate that must be added is 30.23 grams

7 0

3 years ago

Which compounds are lewis acids? select all that apply. (ch3ch2)2hc+ cl3c− ch3nh2 bbr3?

alexandr402 [8]

The Lewis acids are electron pair acceptors due to the availability of vacant orbitals they accept electrons from the donor compounds.

$(CH_3CH_2)_2CH^{+}$ is a Lewis acid due to the unfilled valence shell on carbon atom (possessing positive charge) it accepts electron readily.
$CCl_{3}^{-}$ is not a Lewis acid due to the presence of negative charge which represents that there are electrons available for donation.
$CH_3NH_2$ is not a Lewis acid due to the presence of lone pair on nitrogen which is easily donated to the acceptors.
$BBr_3$ is a Lewis acid due to the availability of vacant p-orbital on boron atom.

Hence, $(CH_3CH_2)_2CH^{+}$ and $BBr_3$ are Lewis acids.

3 0

3 years ago

Glucose and fructose are monosaccharides that have the same chemical formula, C6H12O6. However, they do not react the same chemi

wariber [46]

Monosaccharides are the simplest carbohydrates. Although glucose and fructose have the same molecular formula they have different structures or the atoms are arranged differently from each other and this is evident in the way they react, behave and in their properties.

5 0

2 years ago