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4 years ago

Arrange these elements according to atomic radius. Sr, Ba, Be, Ca, Mg

Chemistry

1 answer:

vovangra [49]4 years ago

6 0

To arrange these elements according to the atomic radius (smallest to largest) would be:

Be, Mg, Ca, Sr, Ba

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Convert 12 meters per second into miles per hour.

Kryger [21]

26.843 miles per hour

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3 years ago

13. Classify as man-made or natural extinction: Massive impact from asteroid or comet.

NISA [10]

Answer:

Natural extinction

Explanation:

Man doesn't play a part in space objects causing extinction

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3 years ago

Can someone tell me how much does 2 drops of food coloring weight?

alex41 [277]

Um definitely under .00001

6 0

3 years ago

Read 2 more answers

Many moderately large organic molecules containing basic nitrogen atoms are not very soluble in water as neutral molecules, but

alukav5142 [94]

Answer:

a) For nicotine, the protonated form is the present in stomach.

b) For caffeine, the neutral base form is the present in stomach.

c) For Strychinene, the protonated form is the present in stomach.

d) For quinine, the protonated form is the present in stomach.

Explanation:

In a basic dissociation for molecules with basic nitrogen, the equilibrium is:

A + H₂O ⇄ AH⁺ + OH⁻

Where A is neutral base and AH⁺ is protonated form

The basic dissociation constant, kb, is:

$K_{b} = \frac{[AH^+][OH^-]}{[A]}$

As pH in stomach is 2,5:

[OH] = $10^{-[14-pH]}$

[OH] = 3,16x10⁻¹² M

Thus:

$\frac{K_{b}}{3,16x10^{-12}} =\frac{[AH^+]}{[A]}$ (1)

Using (1) it is possible to know if you have the neutral base or the protonated form, thus:

(a) nicotine Kb = 7x10^-7

$\frac{K_{b}}{3,16x10^{-12}} =\frac{[AH^+]}{[A]}$

$\frac{7x10^{-7}}{3,16x10^{-12}} =\frac{[AH^+]}{[A]}$

$221359 = \frac{[AH^+]}{[A]}$

[AH⁺}>>>>[A]

For nicotine, the protonated form is the present in stomach

(b) caffeine,Kb= 4x10^-14

$\frac{K_{b}}{3,16x10^{-12}} =\frac{[AH^+]}{[A]}$

$\frac{4x10^{-14}}{3,16x10^{-12}} =\frac{[AH^+]}{[A]}$

$0,0127 = \frac{[AH^+]}{[A]}$

[AH⁺}<<<<[A]

For caffeine, the neutral base form is the present in stomach

(c) strychnine Kb= 1x10^-6

$\frac{K_{b}}{3,16x10^{-12}} =\frac{[AH^+]}{[A]}$

$\frac{1x10^{-6}}{3,16x10^{-12}} =\frac{[AH^+]}{[A]}$

$314456 = \frac{[AH^+]}{[A]}$

[AH⁺}>>>>[A]

For Strychinene, the protonated form is the present in stomach

(d) quinine, Kb= 1.1x10^-6

$\frac{K_{b}}{3,16x10^{-12}} =\frac{[AH^+]}{[A]}$

$\frac{1,1x10^{-6}}{3,16x10^{-12}} =\frac{[AH^+]}{[A]}$

$347851= \frac{[AH^+]}{[A]}$

[AH⁺}>>>>[A]

For quinine, the protonated form is the present in stomach.

I hope it helps!

7 0

3 years ago

1. A student determines the density of water to be 0.966g/ml at a

lions [1.4K]

Answer:

The percentage error in the measurement is 2.4% 

Explanation:

The measurement made by the student is $0.966 g/cm^3$ .

But the actual value of density is $0.943 g/cm^3$

The formula to calculate percentage error is

percentage error = $\frac{(measured \ value-actual \ value)}{(actual \ value)} \times 100$

Hence percentage error in this case is given by

Percentage error = $\frac{(0.966-0.943)}{0.943} \times 100$

= $\frac{0.023}{0.943} \times 100=2.4%$

A physical quantities value will be determines by various quantities. If errors are made in measuring any of these quantities there will be error in the measurement of the final physical quantity as well.

Here density of a substance is a derived quantity determined by measuring mass and volume of that substance. If errors are made in mass and volume measurements the density value will also be erroneous.

4 0

3 years ago