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2 years ago

How many MOLECULES are in 50.0 grams of lithium phosphate?

1 answer:

8 0

Answer: 2.60 x 10^23 molecules

50.0 grams x (1 mol/115.79 grams) = 0.431816219 moles

0.431816219 mol x (6.02 x 10^23 molecules/1 mol) = 2.599533638 x 10^23 molecules (final answer is rounded)

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In the lewis structure of ch3oh, how many lone pairs of electrons are there? in the lewis structure of ch3oh, how many lone pair

Lunna [17]

The structure of Methanol (CH₃OH) is shown below. This structure contains 2 lone pair of electrons on oxygen (highlighted red). Electronic configuration of oxygen is,

Oxygen = 8 = 1s², 2s², 2px², 2py¹, 2pz¹

There are six electrons in valence shell of oxygen, among these six electrons two electrons are unpaired and involved in forming covalent bond with hydrogen and carbon, while remaining 4 electrons in pair (i.e. 2s², 2px²) exists as lone pairs.

7 0

3 years ago

Complete the following single replacement reaction. If they don’t react, just write “NR”

Kipish [7]

Here we have to complete the given single replacement reactions.

The replacement reactions are-

1) Fe (s) + CuCl₂ (aq) → FeCl₂ (aq) + Cu (s)

2) Cu (s) + FeCl₂ (aq) → NA

3) K (s) + NiBr₂ (aq) → NA

4) Ni (s) + KBr (aq) → NiBr₂ (aq) + K (s)

5) Zn (s) + Ca(NO₃)₂ (aq) → Zn(NO₃)₂ (aq) + Ca (s)

6) Ca (s) + Zn(NO₃)₂ (aq) → NA

The replacement reactions can be explained in light of the redox potential.

The standard reduction potential of the half cells involved in these reactions are:

Fe²⁺ + 2e → Fe (E° = -0.441V); Cu²⁺ + 2e → Cu (E° = 0.674V)

Ni²⁺ + 2e → Ni (E° = -0.23V); Zn²⁺ + 2e → Zn (E° = -0.763V)

We know the half cell reactions in which the standard reduction potentials are positive are allowed.

1) The reaction is possible as Cu²⁺/Cu and Fe/Fe²⁺ standard reduction potentials are positive.

2) The reaction is not possible as Cu/Cu²⁺ and Fe²⁺/Fe standard reduction potentials are negative.

3) The reaction is not possible as Ni²⁺/Ni standard reduction potential is negative.

4) The reaction is possible as Ni/Ni²⁺ standard reduction potential is positive.

5) The reaction is possible as Zn/Zn²⁺ standard reduction potential is positive.

6) The reaction is possible as Zn²⁺/Zn standard reduction potential is negative.

4 0

2 years ago

A 50.0g g sample of 16n decays to 12.5g in 14.4 seconds. What is its half life

mixas84 [53]

T is amount after time t
Ao is initial amount 
t is time 
HL is half life 

log (At) = log [ Ao x (1/2)^(t/HL) ] 
log (At) = log Ao + log (1/2)^(t/HL) 
log (At) = log Ao + (t/HL) x log (1/2) 

( log At - log Ao) / log (1/2) = t / HL 
log (At/Ao) / log (1/2) = t / HL 

HL = t / [( log (At / Ao)) / log (1/2) ] 

HL = 14.4 s / [ ( log (12.5 / 50) / log (1/2) ] 

HL = 14.4 s / 2 = 7.2 seconds

8 0

3 years ago

How many moles of MgSiO3 are in 237g of the compound?

Anna35 [415]

For this, we first calculate molecular weight of MgSiO₃:
Atomic masses:
Mg = 24
Si = 28
O = 16

Mr = 24 + 28 + 16 x 3
Mr = 100

moles = mass / Mr
moles = 237 / 100
moles = 2.37

6 0

3 years ago

Gaseous methane CH4 reacts with gaseous oxygen gas O2 to produce gaseous carbon dioxide CO2 and gaseous water H2O. What is the t

Murrr4er [49]

Answer:

50.8 g

Explanation:

Equation of reaction.

$CH_4 + 2O_2 \to CO_2 + 2H_2O$

From the given information, the number of moles of methane = mass/ molar mass

= 15.4 g / 16.04 g/mol

= 0.960 mol

number of moles of oxygen gas = 90.3 g / 32 g/ mol

= 2.82 mol

Since 1 mol of methane requires 2 moles of oxygen

Then 0.960 mol of methane will require = 0.960 mol × 2 = 1.92 mol of oxygen gas

Thus, methane serves as a limiting reagent.

2.82 mol oxygen gas will result in 2.82 moles of water

So, the theoretical yield of water = moles × molar mass

= 2.82 mol × 18.01528 g/mol

= 50.8 g

8 0

2 years ago