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Elis [28]
2 years ago
6

Why is a control needed in a valid experiment?

Chemistry
1 answer:
aliina [53]2 years ago
5 0
You need a control so you have something to compare the experimental group on-- If you don't have a control group, how will you know what's changed?
You might be interested in
A steel cylinder of oxygen is being store in a room at 25.0 °C under a pressure of 1250 atm. What pressure would be exerted by t
Rudik [331]

Answer:

P₂ = 1312.88 atm

Explanation:

Given data:

Initial temperature = 25°C

Initial pressure = 1250 atm

Final temperature = 40°C

Final pressure = ?

Solution:

Initial temperature = 25°C (25+273.15 = 298.15 K)

Final temperature = 40°C ( 40+273.15 = 313.15 k)

The pressure of given amount of a gas is directly proportional to its temperature at constant volume and number of moles.

Mathematical relationship:

P₁/T₁ = P₂/T₂

Now we will put the values in formula:

1250 atm / 298.15 K = P₂/313.15 K

P₂ = 1250 atm × 313.15 K / 298.15 K

P₂ = 391437.5 atm. K /298.15 K

P₂ = 1312.88 atm

6 0
3 years ago
If all the water in 430.0 mL of a 0.45 M NaCI solution evaporates what is the mass of NaCI will remain
skad [1K]

Answer:

11.31 g.

Explanation:

Molarity is defined as the no. of moles of a solute per 1.0 L of the solution.

M = (no. of moles of solute)/(V of the solution (L)).

<em>∴ M = (mass/molar mass)of NaCl/(V of the solution (L)).</em>

<em></em>

<em>∴ mass of NaCl remained after evaporation of water = (M)(V of the solution (L))(molar mass)</em> = (0.45 M)(0.43 L)(58.44 g/mol) = <em>11.31 g.</em>

6 0
3 years ago
Read 2 more answers
What is this thermodynamic?​
VLD [36.1K]

Answer:

oh coooool

I have one Id it is on ace with maybe 5800 points

maybe this picture will help in something

6 0
2 years ago
What is the major underlying principle of chromatography?.
KatRina [158]
Separation will be achieved if one component adheres to the stationary phase more than the other component does.
6 0
2 years ago
Read 2 more answers
Calculate the percentage of each element in acetic acid, hc2h3o2, and glucose, c6h12o6.
My name is Ann [436]
<em>Acetic acid, HC2H3O2</em>

First, calculate for the molar mass of acetic acid as shown below.
    M = 1 + 2(12) + 3(1) + 2(16) = 60 g

Then, calculating for the percentages of each element.
<em> Hydrogen:</em>
    P1 = ((4)(1)/60)(100%) = <em>6.67%</em>

<em> Carbon:</em>
   P2 = ((2)(12)/60)(100%) = <em>40%</em>

<em>Oxygen</em>
  P3 =((2)(16) / 60)(100%) = <em>53.33%</em>

<em>Glucose, C6H12O6</em>

The molar mass of glucose is as calculated below,
   6(12) + 12(1) + 6(16) = 180

The percentages of the elements are as follow,
 <em> Hydrogen:</em>
   P1 = (12/180)(100%) = <em>6.67%</em>

<em>Carbon:</em>
  P2 = ((6)(12) / 180)(100%) = <em>40%</em>

<em>Oxygen:</em>
  P3 = ((6)(16) / 180)(100%) = <em>53.33%</em>

b. Since the empirical formula of the given substances are just the same and can be written as CH2O then, the percentages of each element composing them will just be equal. 
6 0
3 years ago
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