Someone help me with this question with steps please!!!

What mechanical waves needs a medium to travel through?

ValentinkaMS [17]

A) all mechanical waves need a medium to travel through.
This is true because mechanical waves move in a wave like manner at the atomic level. This is why an table vibrates when you put a speaker on top of it .

5 0

2 years ago

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What volume of 6.9 M NaOH is needed to completely titrate 0.42 L of 2.39 M phosphoric acid according to

kirill115 [55]

Taking into account the definition of molarity and the stoichiometry of the reaction, the correct option is option C) 0.44 L of 6.9 M NaOH is needed to completely titrate 0.42 L of 2.39 M phosphoric acid.

The balanced reaction is:

H₃PO₄ (aq) + 3 NaOH (aq) → Na₃PO₄ (aq) + 3 H₂O(aq)

Then, by stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

H₃PO₄: 1 mole
NaOH: 3 moles
Na₃PO₄: 1 mole
H₂O: 3 moles

Molarity is the number of moles of solute that are dissolved in a given volume.

Molarity is determined by:

$Molarity=\frac{number of moles of solute}{volume}$

Molarity is expressed in units $\frac{moles}{liter}$ .

In this case, 0.42 L of 2.39 M phosphoric acid reacts. So, by definition of molarity, the number of moles that participate in the reaction is calculated as:

$2.39 \frac{moles}{liter}=\frac{number of moles of phosphiric acid}{0.42 liters}$

Solving:

number of moles of phosphiric acid= 2.39 $\frac{moles}{liter}$ * 0.42 liters

number of moles of phosphiric acid= 1.0038 moles ≅ 1 mole

Approaching 1 mole of the amount of phosphoric acid required, then by stoichiometry of the reaction, 3 moles of NaOH are necessary to react with 1 mole of the acid.

Then by definition of molarity and knowing that 6.9 M NaOH is needed, you can calculate the necessary volume amount of NaOH by:

$6.9 \frac{moles}{liter} =\frac{3 moles}{volume}$

Solving:

6.9 $\frac{moles}{liter}$ * volume= 3 moles

$volume=\frac{3 moles}{6.9\frac{moles}{liter} }$

volume= 0.44 L

The correct option is option C) 0.44 L of 6.9 M NaOH is needed to completely titrate 0.42 L of 2.39 M phosphoric acid.

Learn more about molarity with this example: <u>brainly.com/question/15406534?referrer=searchResults</u>

5 0

2 years ago

What is the oxidation state of nitrogen in nano2

TiliK225 [7]

Answer:

Therefore, the oxidation state of N in NaNO₂ is +3

Explanation:

Problem: calculating the oxidation state of nitrogen N in NaNO₂

let us denote the oxidation number of Nitrogen as N:

We know from the periodic table that Na has an oxidation number of +1 i.e it will readily want to lose 1 electron so as to complete its octet.

Oxygen is known to have an oxidation number of -2

Summation of the oxidation number of each atoms is 0 for neutral compound.

Therefore to calculate the oxidation state of Nitrogen in NaNO₂, we express as:

+1 + N + (-2 x 2) = 0

1 + N = 4

N = 4-1 = +3

Therefore, the oxidation state of N in NaNO₂ is +3

3 0

3 years ago

Zach needs to make a 2.75 m solution of NaOH(molar mass=40.00g/mol) using 350. g of water. What mass of NaOH should he dissolve

goldfiish [28.3K]

Molality = number of mol solute/ 1000 g solvent = (2.75 mol NaOH)/1000g water

$\frac{2.75( mol NaOH)}{1000(g/ water)} = \frac{x (mol NaOH)}{350(g/water)} 


$ ,
$x= \frac{2.75*350}{1000} = 0.963 (mol NaOH)

$ $0.963 (mol NaOH)* \frac{40.00 (g NaOH)}{1 ( mol NaOH)} =38.5 (g NaOH)$

3 0

3 years ago

What is the mass of a nitrogen dioxide molecule?

lakkis [162]

The molar mass of nitrogen dioxide to the nearest gram-per-mole is 46 g/mol.

8 0

3 years ago

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