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4 years ago

Calculate the number of moles in 456 g of lead, Pb

Chemistry

1 answer:

Vlad [161]4 years ago

3 0

Answer:

Number of moles = 2.2 mol

Explanation:

Given data:

Number of moles of lead = ?

Mass of lead = 456 g

Solution:

Formula:

Number of moles = mass/ molar mass

Molar mass of lead = 207.1 g/mol

Now we will put the values in formula:

Number of moles = 456 g/ 207.1 g/mol

Number of moles = 2.2 mol

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Pls help and i will mark brainliest

myrzilka [38]

Answer:

No. 3 lithium

Explain that lithium has 3 protons and 3 electrons. There are 2 electrons on the first energy level and 1 electron on the second

No. 4 Hydrogen (H) and helium (He) have a valence shell containing one and two electrons respectively. They make up the first period (row) of the periodic table. Their valence electron/s are in the first energy level (n=1) , as is denoted by 1s1 and 1s2 .

That's all i dont know if this is right though. 

6 0

3 years ago

Read 2 more answers

I need to know the weighted average please!

maria [59]

Answer:

63.5456 amu

Explanation:

$0.6917*62.9296+0.3083*64.9278= 63.5456\ amu$

8 0

3 years ago

Calculate the formal charges of the atoms in co co2 and co32-

Dimas [21]

Every element in the compound has its own formal charge. The formula is:
Formal charge = Valence electrons - Nonbonding electrons - Bonding electrons/2
Let the Lewis structure of the compound aid you.

1. For CO:
Formal charge of C = 4 - 2 - 6/2 = -1
Formal charge of O = 6 - 2 - 6/2 = +1

2. For CO₂:
Formal charge of C = 4 - 0 - 8/2 = 0
Formal charge of each O = 6 - 4 - 4/2 = 0

3. For CO₃²⁻:
Formal charge of C: 4 - 0 - 8/2 = 0
Formal charge of two O's single-bonded to C = 6 - 6 - 2/2 = -1
Formal charge of the O double-bonded to C = 6 - 4 - 4/2 = 0

6 0

4 years ago

The ratio of chlorine to hydrogen chloride in the reaction H2(g) + Cl2 (g) -> 2 HCl(g) is

cupoosta [38]

It is a simple stoichiometry problem. We have been given with balanced equation and 5.00 moles of HCl and have to calculate the moles of H2.

From the balanced equation it is being clear that 2 moles of HCl are produced by 1 mole of H2. so, 1 mole of HCl will be produced by 1/2 moles of H2. So, the mole ratio of H2 and HCl is 1:2 
to calculate the moles of H2 for the given moles of HCl, multiply the moles of HCl by the mole ratio of H2 and HCl. 

5.00 mole HCl x (1 mole H2/ 2 mole HCl) 
= 2.50 mole H2 
so, to produce 5.00 moles of HCl, 2.50 moles of H2 are required.

8 0

3 years ago

Why are the concentrations of [H3O+] and [OH−] equal in pure water?

kotegsom [21]

Answer : The correct option is, (A) $[H_3O^+]=[OH^-]$ because one of each is produced every time an $[H^+]$ transfers from one water molecule to another.

Explanation :

As we know that, when the two water molecule combine to produced hydronium ion and hydroxide ion.

The balanced reaction will be:

$HOH+HOH\rightarrow H_3O^++OH^-$

Acid : It is a substance that donates hydrogen ion when dissolved in water.

Base : It is a substance that accepts hydrogen ion when dissolved in water.

From this we conclude that, the hydrogen ion are transferred from one water molecule to the another water molecule to form hydronium ion and hydroxide ion. In this reaction, one water molecule will act as a base and another water molecule will act as an acid.

Hence, the correct option is, (A)

3 0

4 years ago