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3 years ago

What element in the second period has the largest atomic radius?

1 answer:

6 0

The correct option is D.
The elements in the second period are lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine and neon. In the second period, the atomic radius of the elements decreases across the period, thus lithium has the highest atomic radius of 152 picometer while neon has the least [67 picometer].

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Calculate the pH of a solution that contains 2.4 × 10 -5 M H 3O at 25°C. 9.38 11.60 4.62 4.17 2.40

lutik1710 [3]

Answer:

4.62

Explanation:

Using the equation -log[H3O+] = pH,

-log(2.4 x 10^-5) = 4.62

3 0

3 years ago

Read 2 more answers

Find the enthalpy of neutralization of HCl and NaOH. 137 cm3 of 2.6 mol dm-3 hydrochloric acid was neutralized by 137 cm3 of 2.6

liraira [26]

Answer : The correct option is, (D) 89.39 KJ/mole

Explanation :

First we have to calculate the moles of HCl and NaOH.

$\text{Moles of HCl}=\text{Concentration of HCl}\times \text{Volume of solution}=2.6mole/L\times 0.137L=0.3562mole$

$\text{Moles of NaOH}=\text{Concentration of NaOH}\times \text{Volume of solution}=2.6mole/L\times 0.137L=0.3562mole$

The balanced chemical reaction will be,

$HCl+NaOH\rightarrow NaCl+H_2O$

From the balanced reaction we conclude that,

As, 1 mole of HCl neutralizes by 1 mole of NaOH

So, 0.3562 mole of HCl neutralizes by 0.3562 mole of NaOH

Thus, the number of neutralized moles = 0.3562 mole

Now we have to calculate the mass of water.

As we know that the density of water is 1 g/ml. So, the mass of water will be:

The volume of water = $137ml+137ml=274ml$

$\text{Mass of water}=\text{Density of water}\times \text{Volume of water}=1g/ml\times 274ml=274g$

Now we have to calculate the heat absorbed during the reaction.

$q=m\times c\times (T_{final}-T_{initial})$

where,

q = heat absorbed = ?

$c$ = specific heat of water = $4.18J/g^oC$

m = mass of water = 274 g

$T_{final}$ = final temperature of water = 325.8 K

$T_{initial}$ = initial temperature of metal = 298 K

Now put all the given values in the above formula, we get:

$q=274g\times 4.18J/g^oC\times (325.8-298)K$

$q=31839.896J=31.84KJ$

Thus, the heat released during the neutralization = -31.84 KJ

Now we have to calculate the enthalpy of neutralization.

$\Delta H=\frac{q}{n}$

where,

$\Delta H$ = enthalpy of neutralization = ?

q = heat released = -31.84 KJ

n = number of moles used in neutralization = 0.3562 mole

$\Delta H=\frac{-31.84KJ}{0.3562mole}=-89.39KJ/mole$

The negative sign indicate the heat released during the reaction.

Therefore, the enthalpy of neutralization is, 89.39 KJ/mole

3 0

4 years ago

Which substance is the limiting reactant when 4.0 g of sulfur reacts with 6.0 g of oxygen and 8.0 g of sodium hydroxide accordin

Marysya12 [62]

C, NaOH(aq) is the answer

6 0

3 years ago

List the atomic numbers of the elements in period 2

lyudmila [28]

I am not sure but if you google the question it brings up a table :P

4 0

3 years ago

A throat spray is 1.40% by mass Phenol, C6H5OH in water. If the solution has a density of 0.9956 g/ml, calculate the molarity of

myrzilka [38]

<u>Answer:</u> The molarity of solution is 1.08 M

<u>Explanation:</u>

We are given:

(m/m) of phenol = 1.40 %

This means that 1.40 g of phenol is present in 100 g of solution.

To calculate volume of solution, we use the equation:

$\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}$

Density of solution = 0.9956 g/mL

Mass of solution = 100 g

Putting values in above equation, we get:

$0.9956g/mL=\frac{100g}{\text{Volume of solution}}\\\\\text{Volume of solution}=100.442mL$

To calculate the molarity of solution, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Volume of solution (in mL)}}$

We are given:

Mass of solute (phenol) = 1.40 g

Molar mass of phenol = 94.11 g/mol

Volume of solution = 100.442 mL

Putting values in above equation, we get:

$\text{Molarity of solution}=\frac{1.40g\times 1000}{94.11g/mol\times 100.442mL}\\\\\text{Molarity of solution}=0.15M$

Hence, the molarity of solution is 0.15 M

8 0

3 years ago