Ask question

Ask question

All categories

3 years ago

11

Read the article looking at leavse and answer the question. Why causes leaves to change color in the autum? Is the change physic

al or chemical?

1 answer:

guajiro [1.7K]3 years ago

8 0

It’s physical property

Explaination: hehehehehe

You might be interested in

The atomic weight of copper is 63.546 amu. The two naturally occuring isotopes of copper have the following masses 63Cu, 62.9298

strojnjashka [21]

Answer:

The percent isotopic abundance of Cu-65 is 30.79 %.

The percent isotopic abundance of Cu-63 is 69.21 %.

Explanation:

we know there are two naturally occurring isotopes of carbon, Cu-63 (62.9298 amu) and Cu-65 (64.9278 amu)

First of all we will set the fraction for both isotopes

X for the isotopes having mass 62.9298 amu

1-x for isotopes having mass 64.9278 amu

The average atomic mass of copper is 63.546 amu.

we will use the following equation,

62.9298 x + 64.9278 (1-x) = 63.546

62.9298x + 64.9278 - 64.9278x = 63.546

62.9298x - 64.9278x = 63.546 - 64.9278

-1.998 x = -1.3828

x=-1.3828 / -1.998

x= 0.6921

0.6921 × 100 = 69.21 %

69.21 % is abundance of Cu-63 because we solve the fraction x.

now we will calculate the abundance of Cu-65.

(1-x)

1-0.6921 = 0.3079

0.3079 × 100 = 30.79 %

30.79 % for Cu-65.

6 0

3 years ago

In general, ionic compounds have

Solnce55 [7]

HELLO have a nice day

7 0

3 years ago

At rest, a neuron has a lower concentration of sodium than the surrounding fluid. The neuron also has a higher concentration of

pshichka [43]

Answer:

a. Remaining at rest requires the use of ATP.

Explanation:

The resting membrane potential is maintained by the sodium-potassium pump. The sodium potassium pump does this by actively pumping sodium ions out of the cell and potassium ions inside the cell in a ratio of 3:2. This movement of ions by the sodium-potassium pump is against their concentration gradient. In a neuron at rest, there are more sodium ions outside the cell than there are inside the cell. Also, there are are more potassium ions inside the cell than there are outside the cell. However, there are ion channels through which these ions enter and leave the cell. Sodium ion channels allow sodium to enter the cell following its concentration gradient, whereas, potassium ion channels allow potassium to leave the cell following its concentration gradient. However, more potassium ions leave the cell than do sodium ions enter the cell because of the higher permeability of the cell to potassium ions.

In order to maintain the resting membrane potential, the sodium potassium pump powered by the hydrolysis of an ATP molecules pumps sodium ions out of the cell and potassium ions into the cell.

<em>Therefore, the correct option is A, as ATP is needed by the sodium-potassium pump in order to maintain the resting membrane potential.</em>

6 0

3 years ago

The layering of rock horizontally is for the __________ only.

Helga [31]

Answer:

A

Explanation:

7 0

3 years ago

A chemist added an excess of sodium sulfate to a solution of a soluble barium compound to precipitate all of the barium ion as b

AnnyKZ [126]

Answer : The mass percentage of barium in the compound is, 53.8 %

Explanation : Given,

Mass of barium compound = 441 mg

Mass of barium sulfate = 403 mg = 0.403 g (1 mg = 0.001 g)

The balanced chemical reaction will be:

$Ba^{2+}(aq)+Na_2SO_4(aq)\rightarrow BaSO_4(s)+2Na^+(aq)$

First we have to calculate the moles of $BaSO_4$

$\text{Moles of }BaSO_4=\frac{\text{Mass of }BaSO_4}{\text{Molar mass of }BaSO_4}$

Molar mass of $BaSO_4$ = 233.38 g/mole

$\text{Moles of }BaSO_4=\frac{0.403g}{233.38g/mole}=0.001727mole$

Now we have to calculate the moles of barium ion.

From the balanced chemical reaction, we conclude that

As, 1 mole of barium sulfate produced from 1 mole of barium ion

So, 0.001727 mole of barium sulfate produced from 0.001727 mole of barium ion

Now we have to calculate the mass of barium ion.

$\text{ Mass of }Ba^{2+}=\text{ Moles of }Ba^{2+}\times \text{ Molar mass of }Ba^{2+}$

Molar mass of barium = 137.3 g/mol

$\text{ Mass of }Ba^{2+}=(0.001727moles)\times (137.3g/mole)=0.2371g$

Now we convert the mass of barium ion from gram to mg.

Conversion used : (1 g = 1000 mg)

Mass of barium ion = 0.2371 g = 237.1 mg

Now we have to calculate the mass percentage of barium in the compound.

Mass percent of barium = $\frac{237.1mg}{441mg}\times 100=53.8\%$

Thus, the mass percentage of barium in the compound is, 53.8 %

8 0

4 years ago