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myrzilka [38]
3 years ago
15

A chemistry student needs 30,0 mL of pentane for an experiment. By consulting the CRC Handbook of Chemistry and Physics, the stu

dent discovers that the density of pentane is . Calculate the mass of pentane the student should weigh out. Round your answer to significant digits.
Chemistry
1 answer:
Marta_Voda [28]3 years ago
8 0

Answer:

1.878g

Explanation:

Volume = 30.0ml

Density = 0.626gcm−3

Mass = ?

Be careful in this kind of questions to check for the units. In this case one has to remember 1 mL equal 1 cm³ so density = 0.626g/ml

The relationship between all three parameters is given by the equationn below;

Mass = Density * Volume

Mass = 0.626g/ml * 30 = 1.878g

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What is the type of weak bond between the hydrogen of one molecule and the nitrogen of another molecule, where the two don't act
Aliun [14]
<h2>Hydrogen Bonding</h2>

Explanation:

  • Hydrogen bonding is a type of weak bond.
  • Hydrogen Bonding occurs when the hydrogen atom of one molecule is bonded with a molecule of high electronegativity element like nitrogen of another molecule.
  • It is a type of dipole-dipole interations.
  • The nitrogen is a highly electronegative element that forms a weak bond with the hydrogen atom of another molecule with dipole-dipole interaction.
  • Hydrogen bonds are weaker than covalent and ionic bonds.
  • Therefore the type of bond is Hydrogen bond.
8 0
3 years ago
If 38.5 grams of potassium react with excess oxygen gas, how many grams of potassium oxide can be produced? 4K + O2 yields 2K2O
Lera25 [3.4K]

Answer:

46.40 g.

Explanation:

  • It is a stichiometric problem.
  • The balanced equation of the reaction: 4K + O₂ → 2K₂O.
  • It is clear that 4.0 moles of K reacts with 1.0 mole of oxygen produces 2.0 moles of K₂O.
  • We should convert the mass of K (38.5 g) into moles using the relation:

<em>n = mass / molar mass,</em>

n = (38.5 g) / (39.098 g/mol) = 0.985 mole.

<em>Using cross multiplication:</em>

4.0 moles of K produces → 2.0 moles of K₂O, from the stichiometry.

0.985 mole of K produces → ??? moles of K₂O.

∴ The number of moles of K₂O produced = (0.985 mole) (2.0 mole) / (4.0 mole) = 0.4925 mole ≅ 0.5 mole.

  • Now, we can get the mass of K₂O:

∴ mass = n x molar mass = (0.5 mole) (94.2 g/mol) = 46.40 g.

6 0
3 years ago
One way to represent a model of an atom is in a drawing. What is another way to show an atomic model? ​
mamaluj [8]

I think by writing electronic configuration.

7 0
2 years ago
The teacher shows students a pictorial model of an atom. Which element is
frutty [35]

Answer:

C. Fluorine because the model has 9 protons which is represented by the atomic number

Explanation:

We usually identify an element by the number of protons in them. The number of protons is the atomic number of an atom.

  • Every atom has a specific number of protons in them.
  • This number of protons is the atomic number.
  • According to the periodic law, atoms are arranged on the periodic table based on their atomic number.
  • The given fluorine atom has 9 protons which represents the atomic number of the atom.
  • This way, the given number clearly shows the right model for identifying the chemical specie.
4 0
3 years ago
Determine the number of moles in 382.5g of CO-2
exis [7]

Answer: 8.691 mols of CO₂

Explanation:

To find the number of moles in a given grams, you want to use the molar mass.

Let's first find the molar mass of CO₂.

Carbon's molar mass is 12.011 g/mol

Oxygen's molar mass is 15.999 g/mol

To find molar mass of CO₂, we want to add up the molar mass of carbon and oxygen. Remember, there are 2 Oxygens so we need to mulitply that by 2.

12.011+2(15.999)=44.009 g/mol

Now that we have molar mass, we can convert 382.5 g to mols.

382.5g*\frac{1 mol}{44.009g} =8.691 mol

There are about 8.691 mols of CO₂.

5 0
3 years ago
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