3 years ago

We can use thin layer chromatography to check if Starbuck coffee has caffeine. True False

Chemistry

1 answer:

Katarina [22]3 years ago

5 0

Answer:

false?

Explanation:

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The compound Xe(CF3)2 decomposes in afirst-order reaction to elemental Xe with a half-life of 30. min.If you place 7.50 mg of Xe

Irina-Kira [14]

Answer:

$t=147.24\ min$

Explanation:

Given that:

Half life = 30 min

$t_{1/2}=\frac{\ln2}{k}$

Where, k is rate constant

So,

$k=\frac{\ln2}{t_{1/2}}$

$k=\frac{\ln2}{30}\ min^{-1}$

The rate constant, k = 0.0231 min⁻¹

Using integrated rate law for first order kinetics as:

$[A_t]=[A_0]e^{-kt}$

Where,

$[A_t]$ is the concentration at time t

$[A_0]$ is the initial concentration

Given that:

The rate constant, k = 0.0231 min⁻¹

Initial concentration $[A_0]$ = 7.50 mg

Final concentration $[A_t]$ = 0.25 mg

Time = ?

Applying in the above equation, we get that:-

$0.25=7.50e^{-0.0231\times t}$

$750e^{-0.0231t}=25$

$x=\frac{\ln \left(30\right)}{0.0231}$

$t=147.24\ min$

6 0

3 years ago

5. What volume of silver metal will weigh exactly 4500.0 g. The density of silver is 20.5 g/cm.

Vitek1552 [10]

Answer:

The answer is

Explanation:

The volume of a substance when given the density and mass can be found by using the formula

$volume = \frac{mass}{density} \\$

From the question

mass = 4500 g

density = 20.5 g/cm³

We have

$volume = \frac{4500 }{20.5} \\ = 219.51219...$

We have the final answer as

Hope this helps you

8 0

3 years ago

Element R and Element Q have the same number of valence electrons. These elements have similar chemical behavior, but element R

I am Lyosha [343]

Answer:

I dont now because I am in 6 class

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3 years ago

Elements consist of tiny particles called

Nutka1998 [239]

The answer is atoms good luck

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3 years ago

As ________________ increases, air pressure decreases. A) pollution B) water vapor C) radiation D) altitude

lara [203]

Answer:

d or b

Explanation:

8 0

3 years ago