How many molecules are in 1 mole of H2O molecules?

How can scientists determine what kind of atoms are in stars and nebulas?

statuscvo [17]

Each element absorbs light at specific wavelengths unique to that atom. When astronomers look at an object's spectrum, they can determine its composition based on these wavelengths.
Not sure if this is 100% but I hope it helps.

4 0

3 years ago

How many grams of He are necessary to fill a balloon having a volume of 4.50 × 10^{3} mL to a pressure of 1.14 × 10^{3} torr at

lana [24]

The mass in grams of He are necessary to fill a balloon having a volume of 4.50×10³ mL to a pressure of 1.14×10³ torr at 25.0ºC is 1.104 grams.

<h3>How do we calculate the grams from moles?</h3>

Mass (W) in grams from moles (n) will be calculated by using the below equation:
n = W/M, where

M = molar mass

Moles of helium gas will be calculated by using the ideal gas equation:

PV = nRT, where

R = universal gas constant = 62.363 L.torr / K.mol

P = pressure of gas = 1.14×10³ torr

V = volume of gas = 4.50×10³ mL = 4.50 L

n = moles of gas = ?

T = temperature = 25.0ºC = 298 K

On putting these values on the ideal gas equation, we get

n = (1140)(4.5) / (62.363)(298) = 5130 / 18584

n = 0.276 moles

Now we convert this moles into mass by using the first equation as:

W = (0.276mol)(4g/mol) = 1.104 g

Hence required mass of helium gas is 1.104 grams.

To know more about ideal gas equation, visit the below link:

brainly.com/question/12873752

#SPJ1

5 0

2 years ago

The volume of a sample of gas at 273 K is 200. liters. If the volume is doubled at constant pressure, what will be the new tempe

gayaneshka [121]

Answer:

New temperature = 546 K

Explanation:

Given that,

Initial volume, V = 200 L

Initial temperature, T = 273 K

We need to find the new temperature if the volume is doubled.

The relation between temperature and volume is direction. If volume is doubled, it means the temperature gets also doubled.

New temperature of the gas = 2(273) = 546 K

8 0

3 years ago

Determine the quantity of bromine atoms in 18.0g of HgBr2 (using factor label method)

Gnoma [55]

Considering the definition of molar mass and Avogadro's Number, the quantity of bromine atoms in 18.0g of HgBr₂ is 6.023×10²² atoms.

<h3>Definition of molar mass</h3>

The molar mass of substance is a property defined as its mass per unit quantity of substance, in other words, molar mass is the amount of mass that a substance contains in one mole.

The molar mass of a compound (also called Mass or Molecular Weight) is the sum of the molar mass of the elements that form it (whose value is found in the periodic table) multiplied by the number of times they appear in the compound.

<h3>Molar mass of HgBr₂</h3>

In this case, you know the molar mass of the elements is:

Hg= 200 g/mole
Br= 79.9 g/mole

So, the molar mass of the compound HgBr₂ is calculated as:

HgBr₂= 200 g/mole + 2×79.9 g/mole

Solving:

HgBr₂= 359.98 g/mole

Definition of Avogadro's Number

Avogadro's Number or Avogadro's Constant is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023×10²³ particles per mole. Avogadro's number applies to any substance.

<h3>Quantity of bromine atoms in 18.0g of HgBr₂</h3>

Factor-label describes a technique to convert one quantity to another quantity. This method uses the fact that any number or expression can be multiplied by one without changing its value; this is, consists in multiply the value you are given, unit of measurement included, by the conversion factor in fraction form.

Finally, knowing that 2 moles of Br are present in 1 mole of HgBr₂, and considering the molar mass of HgBr₂ and the definition on Avogadro's number, the quantity of bromine atoms in 18.0g of HgBr₂ is calculated as:

$18 gr HgBr_{2}\frac{1 mole HgBr_{2}}{359.98 gHgBr_{2}} \frac{2 mole Br}{1 mole HgBr_{2} } \frac{6.023x10^{23}atoms Br }{1 mole Br} =6.023x10^{22}atoms$