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andrezito [222]
4 years ago
8

Stoichiometry. Are my answers right?

Chemistry
1 answer:
OverLord2011 [107]4 years ago
6 0

Answer:

Congratulations. Mostly correct.

Step-by-step explanation:

Part I. Gold

Moles of Au = 35.12 2g × 1/196.97 = 0.1783 mol Au

Atoms of Au = 0.1783 × 6.022 × 10²³/1 = 1.074 × 10²³ atoms Au

Part II. Sucrose

           Molar mass = 342.30 g/mol

Moles of C₁₂H₂₂O₁₁ = 1.202 g × 1/342.30

Moles of C₁₂H₂₂O₁₁ = 0.003 512 mol C₁₂H₂₂O₁₁

Moles of C = 0.003 512 × 12/1 = 0.042 14 mol C

Moles of H = 0.003 512 × 22/1 = 0.077 25 mol H

Moles of O = 0.003 512 × 11/1 = 0.038 63 mol O

Atoms of C = 0.042 14 × 6.022 × 10²³  = 2.538 × 10²² atoms C

Atoms of H = 0.077 25 × 6.022 × 10²³ = 4.652 × 10²² atoms H

Atoms of O = 0.038 63 × 6.022 × 10²³ = 2.326 × 10²² atoms O

<em>Minor Quibbles: </em>

You put the moles of sucrose in the molar mass slot.

You got the wrong exponents for the atoms of C, H, O.

You followed the rules for significant figures for gold, but not for sucrose.

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An unknown metal is dropped into 127 grams of water. The temperature of the water has been raised from 25OC to 28OC. Using the s
Gnesinka [82]

Answer:

he amount of heat gained by the water is 1.59 kJ    

Explanation:

Relation between heat energy, specific heat and temperature change is as follows

Q = mCΔT

where,    Q or q = heat energy

             m = mass

             C = specific heat  =4.186J/g°C

ΔT = (28°C - 25°C) = 3°C

Now, putting the given values into the above formula as follows.

Q = mCΔT

= 127 × 4.186 × 3

= 1594.86 J or 1.59 kJ    

Therefore, we can conclude that the amount of heat gained by the water is 1.59 kJ    

5 0
3 years ago
What is the hybridization of the central atom in CO2? Hybridization = What are the approximate bond angles in this substance? Bo
const2013 [10]

Answer:

sp

Explanation:

Hybridization is the combination of atomic orbitals to yield equivalent hybrid orbitals of appropriate energy which can participate in bonding.

In every compound there is a central atom. The central atom is usually the least electronegative atom in the molecule. In this case the least electronegative atom in the molecule is carbon.

The bond between carbon and oxygen in CO2 is intermittent between a pure double and a pure triple bond. Hence, carbon is sp hybridized.

7 0
3 years ago
what is the molarity of a concentrated hbr solution if the solution is 27.7% hbr by mass and has a density of 1.24 g/ml
givi [52]
Answer: 
         M = No.of moles of solute / Volume of solution in litres
  HBr: H = 1 x 1 = 1       Br = 1 x 80   
             Molar mass : 81 g / mol
  a.  n = 27.7% / 100 =0.277 g / (81 g / mol) = 0.0034 mol
       
       density = 1.24 g/ml ; D= m / v
               
  b.   65.32 ml x 1 L / 1000 mL = 0.065 L

    
   c. M= n / V
          = 0.0034 mol / 0.065 L
       M= 0.052 mol / L

The molarity of the concentrated HBr solution is 0.052 mol/L
          

3 0
4 years ago
An experimenter found that for the hydrolysis of lactose, ΔH° = +0.44 kJ mol–1 and ΔS° = +0.031 kJ mol–1 K–1. ΔG°for this reacti
Ksivusya [100]

Answer:

ΔG° = -8.8 kJ/mol

Explanation:

The standard Gibbs free energy of reaction (ΔG°) can be calculated using the following expression.

ΔG° = ΔH° - T.ΔS°

where,

ΔH°: standard enthalpy of reaction

T: absolute temperature

ΔS°: standard entropy of reaction

At 298 K (the temperature that is usually used), ΔG° for the hydrolysis of lactose is:

ΔG° = ΔH° - T.ΔS°

ΔG° = 0.44 kJ/mol - 298 K × 0.031 kJ/mol.K

ΔG° = -8.8 kJ/mol

7 0
3 years ago
C2H4(g) + H2O(g) ⇌ C2H5OH
Nikitich [7]
Molecular wt if ethene = 28 g/mol
take 14 ÷ 28 = 0.5 mol
since there is a 1:1 ratio between ethene and ethanol one should produce 0.5 mol

MW ethanol = 46
0.5 × 46 = 23 g should be produced.

17.25/23 = 0.75 = 75% Percent yield
6 0
4 years ago
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