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lianna [129]
2 years ago
11

I need help please Which option is chemical change?

Chemistry
1 answer:
MrRa [10]2 years ago
8 0

Answer:

Getting coated with tarnish

Explanation:

Silver, the original substance is combining with a new substance tarnish to make a whole new chemical.

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Given these reactions, where X represents a generic metal or metalloid 1 ) H 2 ( g ) + 1 2 O 2 ( g ) ⟶ H 2 O ( g ) Δ H 1 = − 241
Mazyrski [523]

Answer:

-767,2kJ

Explanation:

It is possible to sum enthalpies of half-reactions to obtain the enthalpy of a global reaction using Hess's law. For the reactions:

1) H₂(g) + ¹/₂O₂(g) ⟶ H₂O(g) ΔH₁= −241.8 kJ

2) X(s) + 2Cl₂(g) ⟶ XCl₄(s) ΔH₂= +361.7 kJ

3) ¹/₂H₂(g) + ¹/₂Cl₂(g) ⟶ HCl (g) ΔH₃= −92.3 kJ

4) X(s) + O₂(g) ⟶ XO₂(s) ΔH₄= − 607.9 kJ

5) H₂O(g) ⟶ H₂O(l) ΔH₅= − 44.0 kJ

The sum of (4) - (2) produce:

6) XCl₄(s) + O₂(g) ⟶ XO₂(s) + 2Cl₂(g) ΔH₆ = ΔH₄ - ΔH₂ = -969,6 kJ

(6) + 4×(3):

7) XCl₄(s) + 2H₂(g) + O₂(g) ⟶ XO₂(s) + 4HCl(g) ΔH₇ = ΔH₆ + 4ΔH₃= -1338,8 kJ

(7) - 2×(1):

8) XCl₄(s) + 2H₂O(g) ⟶ XO₂(s) + 4HCl(g) ΔH₈ = ΔH₇ - 2ΔH₁= -855,2kJ

(8) - 2×(5):

9) XCl₄(s) + 2H₂O(l) ⟶ XO₂(s) + 4HCl(g) ΔH₉ = ΔH₈ - 2ΔH₅= <em>-767,2kJ</em>

I hope it helps!

6 0
3 years ago
The enthalpy change for converting 10.0 g of ice at -25.0 °C to water at 90.0 °C is __________ kJ. The specific heats of ice, wa
Nina [5.8K]
AH1 = m * c1 * AT1 calculate this for ice (-25C to 0C) AH2 = AHfus(1 mole)=6.01 kJ = 6010 J AH3 = m *c3 * AT3 calculat this for water (0C to 100C) AH4 = AHvap(1mole)=40.67 kJ = 40670 J AH5= m * c5 * AT5 calculate this for steam (100C to 125C) 
Sum ---- AH1+AH2+AH3+AH4+AH5 
Data m=18g (1mole water) 
c1=specific heat ice= 2.09 J/g K c3=specific heat water= 4.18 J/g K c5=specific heat steam= 1.84 J/g K 
AT = (Tend - Tinitial) as this is a difference between temperatures it doesn't matter the units Celsius or Kelvin. Kelvin (K)=Celsius (C)+273.15 
AT1 = 0C - (-25C)= 25C= 273.15K - 248.15K= 25K AT3= 100C - 0C = 100C= 100K AT5= 125C - 100C= 25C=25K
6 0
3 years ago
If you had an object with a mass of 76g and a volume of 22 ml, what is its density? If you cut this object in half, what would b
V125BC [204]
D = M/V = 76g / 22ml = 3.4g/ml

Half ~ D = 38g / 11ml = 3.4g/ml

Even if the object you had was cut in half, it’s density would remain the same.
8 0
3 years ago
Magnesium and iron are metallic elements. How does a mole of magnesium compare with a mole of iron?
Alexus [3.1K]
Given a mole each for iron and magnesium, the number of atoms of each element is equal. Iron has a greater mass due to its greater molecular weight. The correct statement among the choices is D.
6 0
3 years ago
Read 2 more answers
Iron is obtained commercially by the reaction of hematite (Fe2O3) with carbon monoxide. How many grams of iron are produced if 1
kherson [118]
 <span>CO is the limiting reactant 
( 25.0 x 3 = 75 moles of CO are required) 

Moles Fe = 30.0 x 2 / 3 = 20.0 
mass Fe = 20.0 x 55.847 g/mol=1117 g </span><span>

I'm just saying</span>
5 0
3 years ago
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