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4 years ago

Which element has properties most similar to those of chromium

1 answer:

7 0

Chromium is a chemical element with symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard and brittle metal which takes a high polish, resists tarnishing, and has a high melting point.

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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

What is the molar mass for Agno3

Aloiza [94]

Answer:

169.87 g/mol

Explanation:

5 0

3 years ago

If 23.5 g of ammonia (NH3) is dissolved in 1.0 L of solution, what is the molarity?

r-ruslan [8.4K]

Answer:

1.38 M

Explanation:

Need to use the Molarity equation M=n/L

23.5g/ 17.031g/mol NH3 = 1.38 moles

1.38 moles/ 1.0 L = 1.38 M

4 0

2 years ago

Scenes A and B depict changes in matter at the atomic scale:

kaheart [24]

Scene B depicts chemical change in matter at atomic change.

Composition distinguishes a chemical reaction from a physical reaction. In a chemical process, the makeup of the components changes; in a physical change, the appearance, smell, or straightforward exhibition of a sample of matter changes without changing its composition. Despite the fact that we refer to them as physical "reactions," nothing is actually changing. A change in the substance in question's elemental composition is necessary for a reaction to occur. Therefore, from now on, we will simply refer to bodily "reactions" as physical changes.

Learn more about Chemical changes here-

brainly.com/question/23693316

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5 0

1 year ago

In a machine shop, two cams are produced, one of aluminum and one of iron. Both cams have the same mass. Which cam is larger? (a

Lelu [443]

The best and most correct answer among the choices provided by your question is the second choice or letter B.

The iron cam is larger than the aluminum cam even if with the same size.

I hope my answer has come to your help. Thank you for posting your question here in Brainly. We hope to answer more of your questions and inquiries soon. Have a nice day ahead!

5 0

4 years ago

Read 2 more answers