If Junes mother had 3 children July August who is the third child

This happens in diffusion. Choose the correct answer(s)

svlad2 [7]

The answer is d. particles move from an area of high concentration to low concentration.

8 0

2 years ago

When 2 molecules collide, what happens

shepuryov [24]

The answer is A! Hoped it’s sure!
Explanation: A chemical reaction involves breaking bonds in the reactants, rearranging the atoms into new groupings (the products), and forming new bonds in the products.

Hope I was able to help! Mark me brainly it would help a lot!

4 0

3 years ago

Phenolphthalein has a pKa of 9.7 and is colorless in its acid form and pink in its basic form. calculate [In-}/{HIn} for the fol

zvonat [6]

Answer:

1.58x10⁻⁵

2.51x10⁻⁸

0.0126

63.10

Explanation:

Phenolphthalein acts like a weak acid, so in aqueous solution, it has an acid form HIn, and the conjugate base In-, and the pH of it can be calculated by the Handerson-Halsebach equation:

pH = pKa + log[In-]/[HIn]

pKa = -logKa, and Ka is the equilibrium constant of the dissociation of the acid. [X] is the concentrantion of X. Thus,

i) pH = 4.9

4.9 = 9.7 + log[In-]/[HIn]

log[In-]/[HIn] = - 4.8

[In-]/[HIn] = $10^{-4.8}$

[In-]/[HIn] = 1.58x10⁻⁵

ii) pH = 2.1

2.1 = 9.7 + log[In-]/[HIn]

log[In-]/[HIn] = -7.6

[In-]/[HIn] = $10^{-7.6}$

[In-]/[HIn] = 2.51x10⁻⁸

iii) pH = 7.8

7.8 = 9.7 + log[In-]/[HIn]

log[In-]/[HIn] = -1.9

[In-]/[HIn] = $10^{-1.9}$

[In-]/[HIn] = 0.0126

iv) pH = 11.5

11.5 = 9.7 + log[In-]/[HIn]

log[In-]/[HIn] = 1.8

[In-]/[HIn] = $10^{1.8}$

[In-]/[HIn] = 63.10

6 0

3 years ago

The half life of 226/88 Ra is 1620 years. How much of a 12 g sample of 226/88 Ra will be left after 8 half lives?

Aloiza [94]

Answer:

0.0468 g.

Explanation:

The decay of radioactive elements obeys first-order kinetics.

For a first-order reaction: k = ln2/(t1/2) = 0.693/(t1/2).

Where, k is the rate constant of the reaction.

t1/2 is the half-life time of the reaction (t1/2 = 1620 years).

∴ k = ln2/(t1/2) = 0.693/(1620 years) = 4.28 x 10⁻⁴ year⁻¹.

For first-order reaction: kt = lna/(a-x).

where, k is the rate constant of the reaction (k = 4.28 x 10⁻⁴ year⁻¹).

t is the time of the reaction (t = t1/2 x 8 = 1620 years x 8 = 12960 year).

a is the initial concentration (a = 12.0 g).

(a-x) is the remaining concentration.

∴ kt = lna/(a-x)

(4.28 x 10⁻⁴ year⁻¹)(12960 year) = ln(12)/(a-x).

5.54688 = ln(12)/(a-x).

Taking e for the both sides:

256.34 = (12)/(a-x).

∴ (a-x) = 12/256.34 = 0.0468 g.

8 0

3 years ago

If you have a truckload of icecream, a bucket of sauce, a box of peanuts but only 1 cherry, you can only make 1 complete sundae.

MAXImum [283]

Answer:

Only 5 sundaes can be made

The limiting reagent is the peanuts.

Explanation:

The complete question is

A perfect ice cream sundae requires exactly:

• 3 scoops of ice cream

• 2 squirts of chocolate sauce

• 1 spoon of peanuts

• 1 cherry

If you have 7 scoops of ice cream, 3 spoons of peanuts, 5 cherries and 11 squirts of sauce, you can only

make 2 complete sundaes. In this case, the icecream is the limiting reagent.

If you have a truckload of icecream, a bucket of sauce, a box of peanuts but only 1 cherry, you can only make 1 complete sundae. In this case the cherry is the limiting reagent. The limiting reagent is the term given to the ingredient (read: reactant) that has the (stoichiometrically) least amount. The other reactants are said to be in excess. In a reaction the limiting reagent will be totally consumed, and some of the reactant in excess will be leftover.

Critical thinking questions

1. If you have 20 scoops of ice cream, 14 squirts of chocolate sauce, 5 spoons of peanuts and 7 cherries,

how many sundaes can you make and which ingredient is the limiting reagent?

From the ingredients for a a complete sundae given above,

20 scoops of icecream will make 20/3 = 6.66 sundaes

14 squirts of chocolate sauce will make 14/2 = 7 sundaes

5 spoonful of peanuts will make 5/1 = 5 sundaes

7 cherries will make 7/1 = 7 sundaes

From the above, we can work out that only 5 sundaes can be made, and the limiting agent here is peanuts, which has the least amount of sundae that can be made from its available amount.

5 0

3 years ago