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3 years ago

Explain why the periodic table is not a normal table of rows and columns

1 answer:

7 0

The vertical columns on the periodic table are called groups or families because of their similar chemical behavior. All the members of a family of elements have the same number of valence electrons and similar chemical properties. The horizontal rows on the periodic table are called periods.

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reaction 1:CCl4⟶CH4 reaction 2:N2+3H2⟶2H3N reaction 3:2H2+2O2⟶2H2O+Au Which of the chemical reactions are NOT possible according

olga nikolaevna [1]

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Solution: Which of the following chemical reactions is/are NOT possible according to Dalton's atomic theory?a. reaction 1: CCl4 → CH4b. reaction 2: N2 + 3H2 → 2NH3c. reaction 3: 2H2 + O2 → 2H2O + Au

Problem

Which of the following chemical reactions is/are NOT possible according to Dalton's atomic theory?

a. reaction 1: CCl4 → CH4

b. reaction 2: N2 + 3H2 → 2NH3

c. reaction 3: 2H2 + O2 → 2H2O + Au

3 0

3 years ago

s) Suppose we now collect hydrogen gas, H2(g), over water at 21◦C in a vessel with total pressure of 743 Torr. If the hydrogen g

Elenna [48]

This is an incomplete question, here is a complete question.

Suppose we now collect hydrogen gas, H₂(g), over water at 21°C in a vessel with total pressure of 743 Torr. If the hydrogen gas is produced by the reaction of aluminum with hydrochloric acid:

$2Al(s)+6HCl(aq)\rightarrow 2AlCl_3(aq)+3H_2(g)$

what volume of hydrogen gas will be collected if 1.35 g Al(s) reacts with excess HCl(aq)? Express your answer in liters.

Answer : The volume of hydrogen gas that will be collected is 1.85 L

Explanation :

First we have to calculate the number of moles of aluminium.

Given mass of aluminium = 1.35 g

Molar mass of aluminium = 27 g/mol

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

$\text{Moles of aluminium}=\frac{1.35g}{27g/mol}=0.05mol$

The given chemical reaction is:

$2Al(s)+6HCl(aq)\rightarrow 2AlCl_3(aq)+3H_2(g)$

As, hydrochloric acid is present in excess. So, it is considered as an excess reagent.

Thus, aluminium is a limiting reagent because it limits the formation of products.

By Stoichiometry of the reaction:

2 moles of aluminium produces 3 moles of hydrogen gas

So, 0.005 moles of aluminium will produce = $\frac{3}{2}\times 0.05=0.0750mol$ of hydrogen gas

Now we have to calculate the mass of helium gas by using ideal gas equation.

PV = nRT

where,

P = Pressure of hydrogen gas = 743 Torr

V = Volume of the helium gas = ?

n = number of moles of hydrogen gas = 0.075 mol

R = Gas constant = $62.364\text{ L Torr }mol^{-1}K^{-1}$

T = Temperature of hydrogen gas = $21^oC=[21+273]K=294K$

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

$743Torr\times V=0.075mol\times 62.364\text{ L Torr }mol^{-1}K^{-1}\times 294K\\\\V=1.85L$

Hence, the volume of hydrogen gas that will be collected is 1.85 L

8 0

4 years ago

The pH of a solution can be calculated using which formula?

VikaD [51]

Answer:

The formula for calculating pH is pH=−log[H_3O+ ]

pH is the negative logarithm (to base 10) of hydronium ion concentration

The pH Formula can also be expressed as

PH= - log[H+ ]

5 0

3 years ago

If a liquid sample of naphthalene is heated and remains at 218 degrees c until it is completely vaporized, you know that 218 deg

Alexxandr [17]

<span>The correct answer is b. Boiling point, why? because the liquid sample of napthalene is heated and remained at the temperature of 218 degrees celsius, the outcome was that the napthalene was completely vaporized, therefore we are given the scenario that at the temperature of 218 degrees celsius is considered to be the boiling pont of napthalene.</span>

5 0

4 years ago

Read 2 more answers

Silicon has four electrons in its outer energy level. What type of bond is silicon mostly likely to form with other elements? Ex

RideAnS [48]

Since it has 4 electrons, it needs only 4 more to be stable. Therefore, it would share electrons, which is a covalent bond.

Answer: Covalent bond

3 0

3 years ago

Explain why the periodic table is not a normal table of rows and columns​

Explain why the periodic table is not a normal table of rows and columns