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3 years ago

Slimotosis

Chemistry

1 answer:

Flauer [41]3 years ago

4 0

Answer:

Here's what I get

Explanation:

A. Initial observation

Gary's shell had slime and an odour.

B. Independent variable

The independent variable is the one that the experimenter changes.

There are two independent variables: the rubbing with seaweed and the drinking of Dr. Kelp.

C. The dependent variable

The dependent variable is the amount of slime and odour.

D. The conclusion

Sponge Bob can conclude that rubbing the shell with seaweed and drinking Dr. Kelp removes the slime and odour.

However, this was a poorly designed experiment. He doesn't know if it is the seaweed or the Dr. Kelp that gives the result or if he must use both together. He should change only one independent variable at a time.

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Alcohol or acid will travel the furthest up the paper chromatography? pls help thanks and explain

d1i1m1o1n [39]

Answer:

True

Explanation:

Yes.

The distance that the molecules move depends on their solubility in the solvent and the size of the molecules. Heavy molecules will travel slower and therefore travel a shorter distance in the time the chromatography is run.

We know from such things as felt tip pens that colourings can be soluble in different solvents. Water soluble felt pens have colours that are - well - water soluble. Permanent felt pens have colours that are insoluble in water but that are soluble in another solvent. This could well be alcohol.

The water soluble colours may also be soluble in alcohol. The solubility in alcohol will be different from the solubility in alcohol, and so the Rf value ( the distance travelled) will also be different.

Because of the complicated shapes of the colours, the colours may not have the same order in the Rf values in the different solvents.

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3 years ago

What are the various forms of energy?

Fantom [35]

Science has classified energy into two main forms: kinetic energy and potential energy. In addition, potential energy takes several forms of its own. Kinetic energy is defined as the energy of a moving object.

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3 years ago

Read 2 more answers

The radioactive isotope of lead, Pb-209, decays at a rate proportional to the amount present at time t and has a half-life of 3.

Marina86 [1]

Answer:

Therefore it will take 7.66 hours for 80% of the lead decay.

Explanation:

The differential equation for decay is

$\frac{dA}{dt}= kA$

$\Rightarrow \frac{dA}{A}=kdt$

Integrating both sides

ln A= kt+c₁

$\Rightarrow A= e^{kt+c_1}$

$\Rightarrow A=Ce^{kt}$ [ $e^{c_1}=C$ ]

The initial condition is A(0)= A₀,

$\therefore A_0=Ce^{0.k}$

$\Rightarrow C=A_0$

$\therefore A=A_0e^{kt}$ .........(1)

Given that the $Pb_{209}$ has half life of 3.3 hours.

For half life $A=\frac12 A_0$ putting this in equation (1)

$\frac12A_0=A_0e^{k\times3.3}$

$\Rightarrow ln(\frac12)= 3.3k$ [taking ln both sides, $ln \ e^a=a$ ]

$\Rightarrow k=\frac{ln \frac12}{3.3}$

⇒k= - 0.21

Now A₀= 1 gram, 80%=0.8

and A= (1-0.8)A₀ = (0.2×1) gram = 0.2 gram

Now putting the value of k,A and A₀in the equation (1)

$\therefore 0.2=1e^{(-0.21)\times t}$

$\Rightarrow e^{-0.21t}=0.2$

$\Rightarrow -0.21t= ln(0. 2)$

$\Rightarrow t= \frac{ln (0.2)}{-0.21}$

⇒ t≈7.66

Therefore it will take 7.66 hours for 80% of the lead decay.

3 0

3 years ago

At standard temperature and pressure. 0.500 mole of xenon gas occupies

ANEK [815]

Answer:

0.500 mole of Xe (g) occupies 11.2 L at STP.

General Formulas and Concepts:

Gas Laws

STP (Standard Conditions for Temperature and Pressure) = 22.4 L per mole at 1 atm, 273 K

Stoichiometry

Mole ratio
Dimensional Analysis

Explanation:

Step 1: Define

Identify.

0.500 mole Xe (g)

Step 2: Convert

[DA] Set up: $\displaystyle 0.500 \ \text{mole Xe} \bigg( \frac{22.4 \ \text{L Xe}}{1 \ \text{mole Xe}} \bigg)$
[DA] Evaluate: $\displaystyle 0.500 \ \text{mole Xe} \bigg( \frac{22.4 \ \text{L Xe}}{1 \ \text{mole Xe}} \bigg) = 11.2 \ \text{L Xe}$

Topic: AP Chemistry

Unit: Stoichiometry

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2 years ago

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