How many protons and electrons are there in a neutral atom of lithium Np=Ne

What evidence have you discovered to explain how a wave interacts with matter?

Y_Kistochka [10]

Answer:

Three ways that waves may interact with matter are reflection, refraction, and diffraction. Reflection occurs when waves bounce back from a surface that they cannot pass through. Refraction occurs when waves bend as they enter a new medium at an angle and start traveling at a different speed.

Explanation:

7 0

3 years ago

Ions that have the same electron configuration are called

Katena32 [7]

Such ions are said to be isoelectronic

3 0

3 years ago

A 0.21 M solution of a weak acid HA dissociates such that 99.1% of the weak acid remains intact (i.e., remains as HA). To the ne

bixtya [17]

Answer:

pKa = - 1.36012

Explanation:

HA ↔ H+ + A-

∴ Ka = [H+] [A-] / [HA]

pKa = - Log Ka

% dissociates (%α) = ([A-] / [A-] + [HA])×100

∴ %α = 99.1%

∴ C HA = 0.21 M

Mass Balance:

⇒ C HA = [HA] + [A-] = 0.21 M............(1)

Charge balance:

⇒ [H+] = [A-] + [OH-].....[OH-] is neglected, it come from the water

⇒ [H+] = [A-]...............(2)

(2) in (1):

⇒ [HA] = 0.21 - [H+]

replacing in %α:

∴ %α = 99.1% = ([A-]/([A-]+[HA]))×100

⇒ 0.991 = [A-] / [A-] + [HA] = [A-] / 0.21 M

⇒ [A-] = (0.21 M)*(0.991) = 0.20811 M

Replacing in Ka:

⇒ Ka = [H+]² / (0.21 - [H+])

∴ [H+] = [A-] = 0.20811 M

⇒ Ka = (0.20811)² / (0.21 - 0.20811)

⇒ Ka = 22.9152

⇒ pKa = - Log (22.9152)

⇒ pKa = - 1.3601

4 0

3 years ago

The spongy layer of leaves stores water and food. True False

gulaghasi [49]

Answer:

True

Explanation:

The main function of the spongy layer is to temporarily store sugars, and amino acids synthesized in the palisade layer of the leaf (the palisade carries out most of photosynthesis)

3 0

3 years ago

How many grams are in 1.76 x 10^23 atoms of iodine

Mariana [72]

Answer:

$\boxed {\boxed {\sf About \ 37.1 \ grams \ of \ iodine }}$

Explanation:

To convert from atoms to grams, you must first convert atoms to moles, then moles to grams.

1. Convert Atoms to Moles

To convert atoms to grams, Avogadro's number must be used.

$6.022*10^{23}$

This number tells us the number of particles (atoms, molecules, ions, etc.) in 1 mole. In this case, the particles are atoms of iodine.

$\frac{6.022*10^{23} \ atoms \ I }{1 \ mol \ I}$

Multiply the given number of atoms by Avogadro's number.

$1.76*10^{23} \ atoms \ I*\frac{6.022*10^{23} \ atoms \ I }{1 \ mol \ I}$

Flip the fraction so the atoms of iodine will cancel out.

$1.76*10^{23} \ atoms \ I*\frac{ 1 \ mol \ I}{6.022*10^{23} \ atoms \ I}$

$1.76*10^{23}* \frac{1 \ mol \ I}{6.022*10^{23} }$

Multiply so the problem condenses into 1 fraction.

$\frac{1.76*10^{23} \ mol \ I}{6.022*10^{23} }$

$0.2922617071 \ mol \ I$

2. Convert Moles to Grams

Now we must use the molar mass of iodine, which is found on the Periodic Table.

Iodine Molar Mass: 126.9045 g/mol

Use this mass as a fraction.

$\frac{ 126.9045 \ g\ I }{ 1 \ mol \ I}$

Multiply this fraction by the number of moles found above.

$0.2922617071 \ mol \ I*\frac{ 126.9045 \ g\ I }{ 1 \ mol \ I}$

Multiply. The moles of iodine will cancel.

$0.2922617071 *\frac{ 126.9045 \ g\ I }{ 1 }$

The 1 as a denominator is insignificant.

$0.2922617071 *{ 126.9045 \ g\ I }$

$37.08932581 \ g \ I$

3. Round

The original measurement of 1.76*10^23 has 3 significant figures (1, 7, and 6). Therefore we must round our answer to 3 sig figs. For this answer, that is the tenths place.

$37.08932581 \ g \ I$

The 8 in the hundredth place tells us to round the 0 up to a 1.

$\approx 37.1\ g \ I$

There is about 37.1 grams of iodine in 1.76*10^23 atoms.

5 0

4 years ago