Which of the following elements has the lowest electronegativity?

Nick needs 3.5 moles of sodium fluoride (NaF) for a solution he is mixing in the lab. How many grams of NaF does Nick need to me

Minchanka [31]

Answer:

147 g

Explanation:

<em>The number of moles of a substance is the ratio of the mass of the substance and the molar mass of that substance.</em> Mathematically,

mole = mass of substance/molar mass

In this case, Nick needs 3.5 moles of NaF, the molar mass of NaF is calculated as:

23 + 19 = 42 g/mol (Note: Na = 23, F = 19)

Hence,

mass of 3.5 mole NaF = mole x molar mass

= 3.5 x 42 = 147 g.

<em>Hence, Nick would need to measure out </em><em>147 g</em><em> NaF using a suitable weighing balance.</em>

5 0

3 years ago

An unknown compound contains only carbon, hydrogen, nitrogen, and oxygen. Complete combustion of a 2.77 g sample of the compound

alisha [4.7K]

The molecular formula of the unknown compound is determined as C₉H₁₁NO₂.

<h3>Molecular formula of the compound</h3>

The molecular formula is calculated as follows;

CHNO + O₂ ------------> CO₂ + H₂O

Mass of carbon, C: = (6.64 x 12)/44 = 1.81 g in 2.77 g sample

Mass of hydrogen, H: = (1.67 x 2)/18 = 0.186 g in 2.77 g sample

Mass of Nitrogen, N: = (2.77 x 0.143)/1.69 = 0.234 g

Mass of oxygen, O: = 2.77 g - 1.81 g - 0.186 g - 0.234 g = 0.54 g

<h3>molar ratio of the elements: </h3>

C = 1.81 g = 0.15 mol

H = 0.186 g = 0.186 mol

N = 0.234 g = 0.017 mol

O = 0.54 g = 0.0337 mol

divide through with the smallest number of moles (0.017 mol);

C = 9

H = 11

N = 1

O = 2

Molecular formula = C₉H₁₁NO₂

Check the molar mass of the compound = (9 x 12) + (11 x 1) + (14) + (2 x 16) = 165 g/mol

Thus, the molecular formula of the unknown compound is determined as C₉H₁₁NO₂.

Learn more about molecular mass here: brainly.com/question/21334167

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4 0

2 years ago

Why do the elements in a group all behave similarly

Svetradugi [14.3K]

Answer:

See the explanation below, please.

Explanation:

The elements of the periodic table that belong to the same group (each column) have similar physical and chemical properties. This is because they have the same number of electrons in their last electronic layer.

Example of electronic configuration of elements of GROUP IA:

Hydrogen: 1s ^ 1

Lithium: 1s ^ 2 2s ^ 1

6 0

3 years ago

What volume of hydrogen will be produced at STP by the reaction of 67.3 g of tin with excess water according to the following re

VikaD [51]

Answer:

Sn + 2H2O ==> Sn(OH)2 + 2H2

67.3 g Sn x 1 mol/119 g x 2 mol H2/mol Sn x 22.4 L/mole = answer in liters

Explanation:

Sn + 2H2O ==> Sn(OH)2 + 2H2

67.3 g Sn x 1 mol/119 g x 2 mol H2/mol Sn x 22.4 L/mole = answer in liters

5 0

3 years ago

Why bond angle of H2O is maximum then OF2??

Nataly_w [17]

It's lone a little distinction (103 degrees versus 104 degrees in water), and I trust the standard rationalization is that since F is more electronegative than H, the electrons in the O-F bond invest more energy far from the O (and near the F) than the electrons in the O-H bond. That moves the powerful focal point of the unpleasant constrain between the bonding sets far from the O, and thus far from each other. So the shock between the bonding sets is marginally less, while the repugnance between the solitary matches on the O is the same - the outcome is the edge between the bonds is somewhat less.

8 0

3 years ago