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2 years ago

What do atom, molecules, and elements have in common

Chemistry

1 answer:

____ [38]2 years ago

6 0

Answer:

Solids, liquids, gases - all matter - are made up of atoms (or other things, like molecules, that are made from atoms)! ELEMENTS are the kinds of atoms that we can have. Carbon is an element, hydrogen is an element, and so is oxygen. ... Atoms can join together - they form bonds together - to make MOLECULES.

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calculate the mass of 120cc nitrogen present at STP. how many number of molecules are present in it?

Stells [14]

Answer:

$0.15008\ \text{g}$

$3.23\times 10^{21}$

Explanation:

1 mol of nitrogen at STP = 22.4 L = 22400 cc

n = Mol of $N_2$ = $\dfrac{120}{22400}=0.00536\ \text{mol}$

M = Molar mass of $N_2$ = $28\ \text{g/mol}$

$N_A$ = Avogadro's number = $6.022\times 10^{23}\ \text{mol}^{-1}$

Mass of $N_2$ is

$m=nM\\\Rightarrow m=0.00536\times 28\\\Rightarrow m=0.15008\ \text{g}$

Mass of the nitrogen is $0.15008\ \text{g}$

Number of molecules is given by

$nN_A=0.00536\times 6.022\times 10^{23}=3.23\times 10^{21}\ \text{molecules}$

The number of molecules present in it are $3.23\times 10^{21}$

5 0

3 years ago

Based on the equation, how many grams of Br2 are required to react completely with 36.2 grams of AlCl3?

s2008m [1.1K]

Answer:

65.08 g.

Explanation:

For the reaction, the balanced equation is:

2AlCl₃ + 3Br₂ → 2AlBr₃ + 3Cl₂,

2.0 mole of AlCl₃ reacts with 3.0 mole of Br₂ to produce 2.0 mole of AlBr₃ and 3.0 mole of Cl₂.

Firstly, we need to calculate the no. of moles of 36.2 grams of AlCl₃:

n = mass/molar mass = (36.2 g)/(133.34 g/mol) = 0.2715 mol.

Using cross multiplication:

2.0 mole of AlCl₃ reacts with → 3.0 mole of Br₂, from the stichiometry.

0.2715 mol of AlCl₃ reacts with → ??? mole of Br₂.

∴ The no. of moles of Br₂ reacts completely with 0.2715 mol (36.2 g) of AlCl₃ = (0.2715 mol)(3.0 mole)/(2.0 mole) = 0.4072 mol.

∴ The mass of Br₂ reacts completely with 0.2715 mol (36.2 g) of AlCl₃ = no. of moles of Br₂ x molar mass = (0.4072 mol)(159.808 g/mol ) = 65.08 g.

4 0

3 years ago

Someone help me please

vesna_86 [32]

I am pretty sure its b, Ag atoms and localized electrons in silver

3 0

3 years ago

Determine the mass of 9.2 x 10^18 molecules of dinitrogen tetroxide.

steposvetlana [31]

Answer: 1.4x10-3 g N2O4

Explanation: First convert molecules of N2O4 to moles using Avogadro's Number. Then convert moles to mass using the molar mass of N2O4.

9.2x10^18 molecules N2O4 x 1 mole N2O4 / 6.022x10²³ molecules N2O4

= 1.53x10-5 moles N2O4

1.53x10-5 moles N2O4 x 92 g N2O4/ 1 mole N2O4

= 1.4x10-3 g N2O4

4 0

3 years ago

In the chemical reaction: NaOH (s) + H2O Na+ (aq) + OH- (aq), which substance (or substances) is in solution? A. Na+ (aq) only B

bonufazy [111]

Answer:

in a chemical reaction of NaOH with H2O, after NaOH is completely disassociated, we will find Na+ and OH- ions in the solution. (option C).

Explanation:

In a reaction where NaOH is added to H2O.

NaOH is considered a strong base, this means that in an aqueous solution ( in water) it's able to completely disassociate in ions.

There will not remain any NaOH in the solution. This means option D is not correct.

The ions in which NaOH will disassociate are : NaOH → Na+ + OH-

These ions we will find in the solution.

Not only Na+ because NaOH is a strong base, so there will be a lot of OH- ions as well in solution.

This means in a chemical reaction of NaOH with H2O, after NaOH is completely disassociated, we will find Na+ and OH- ions in the solution.

3 0

2 years ago