Which of the following events fail to follow the law of conservation of matter? Select the correct answer below

Which family on the periodic table has a filled outer energy level?

Ede4ka [16]

The family on the periodic table that has a filled outer energy level is VIIIA. The answer is letter D. They are also called the noble gases or inert gases. They are virtually unreactive towards other elements or compounds. They are found in trace amounts in the atmosphere. Their elemental form at room temperature is colorless, odorless and monatomic gases. They also have full octet of eight valence electrons in their highest orbitals so they have a very little tendency to gain or lose electrons to form ions or share electrons with other elements in covalent bonds.

6 0

3 years ago

I what process does a solid change directly into a vapor

Marina86 [1]

Answer:

solid change directly into a vapor in the process known simply as freezing

7 0

3 years ago

Is the largest of Saturn's moons, Charon, larger than Mercury?

vazorg [7]

Answer:

no, Charon is significantly smaller than Mercury

4 0

2 years ago

Match the chemical with the statement that best describes the observed change in the rate of the reaction when the concentration

maria [59]

Answer:

Explanation:

When the amount of H2O2 is doubled while KI is kept constant, the rate of reaction doubles.

When the amount of KI is doubled and the amount of H2O2 is halved, the rate stays nearly constant.

2H2O2 (aq) → O2(g) + 2H2O (l) ------------- first order kinetics reaction.

Catalysts are KI, FeCl3 only, KCl is not a catalyst. Order: KI < MnO2 < Pb < FeCl3.

H2O2 + I– -> IO– + H2O (Step 1)

H2O2 + IO– -> I– + H2O + O2 (Step 2)

It can be seen that the iodine ion (provided by the KI solution) is a product as well as a reactant.

02(g)2Fe? (aq) + 2 H(a) 2 H 2 Fe3 (aq) H2O2(aq) + 2 Fe,Taq) H02(aq) 2 Fe (aq) 2 H (aq)

8 0

2 years ago

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

3 years ago