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harina [27]
3 years ago
5

Which of the following equations represents an exothermic reaction? (Select all that apply.)

Chemistry
2 answers:
frez [133]3 years ago
7 0

Answer:

CH₄ + 2O₂ ⟶ CO₂ + 2H₂O + 212 800 cal

Step-by-step explanation:

CH₄ + 2O₂ ⟶ CO₂ + 2H₂O + 212 800 cal  

The heat is on the right-hand side of the equation, so the reaction is releasing heat.

The reaction is <em>exothermic</em>.

A is <em>wrong</em>. Your sign of ΔH is wrong, because graphite is the more stable form of carbon. We must add energy to graphite to convert it to diamond, so the process is<em> endothermic</em>.

B and D are <em>wrong</em>, because a ΔH > 0 indicates an <em>endothermic</em> reaction.

Elza [17]3 years ago
3 0

Answer:

C (graphite) → C (diamond), ΔH = - 0.45 kcal

CH4 + 2O2 → CO2 + 2H2O + 212,800 cal

Explanation:

exothermic reactions are characterized by releasing heat to the surroundings; the enthalpy change is negative, and the system temperature increases.

NH3 (g) + 12.0 kcal → ½N2 (g) + 3/2 H2 (g): it is not exothermic.

C (graphite) → C (diamond), ΔH = - 0.45 kcal: the reaction is exothermic because ΔH is negative

C + 2S → CS2, ΔH = 27,550 cal: it is not exothermic because the enthalpy change is positive

CH4 + 2O2 → CO2 + 2H2O + 212,800 cal: it is exothermic because it releases heat.

2H2O → 2H2 + O2, ΔH = +58 kcal: it is not exothermic because ΔH is positive.

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A solution of copper sulfate (CuSO4) produced by bioleaching has a concentration of 0.319 g/dm3 Relative atomic masses (Ar): Cu
Tanya [424]

moles Cu produced : 0.002

<h3>Further explanation</h3>

Concentration of copper sulfate (CuSO₄) : 0.319 g/dm³

MW CuSO₄ :

\tt =63.5+32+4\times 16=159.5~g/mol

mol CuSO₄ /dm³ :

\tt \dfrac{0.319}{159.5}=0.002

CuSO₄⇒Cu²⁺ + SO₄²⁻

mol Cu : mol CuSO₄ = 1 : 1 , so mol Cu²⁺=0.002

6 0
3 years ago
1. Silver nitrate will react with aluminum metal, yielding aluminum nitrate and silver metal. If you start with 0.223 moles of a
Archy [21]

Answer:

Explanation:

1)

Given data:

Number of moles of aluminium = 0.223 mol

Mass of silver produced = ?

Solution:

Chemical equation:

3AgNO₃  +   Al  →  3Ag + Al(NO₃)₃

Now we will compare the moles of Al with silver.

                               Al           :            Ag

                                1            :             3

                                0.223   :         3×0.223= 0.669 mol

Grams of silver:

Mass = number of moles × molar mass

Mass = 0.669 mol × 107.87 g/mol

Mass = 72.2 g

2)

Given data:

Number of moles of mercury(II) oxide produced = 3.12 mol

Mass of mercury = ?

Solution:

Chemical equation:

2Hg + O₂  →   2HgO

Now we will compare the moles of mercury with mercury(II) oxide.

                         HgO         :         Hg

                            2            :          2

                          3.12          :       3.12

Mass of Hg:

Mass = number of moles × molar mass

Mass = 3.12 mol × 200.59 g/mol

Mass = 625.84 g

3)

Given data:

Number of moles of dinitrogen pentoxide = 12.99 mol

Mass of oxygen = ?

Solution:

Chemical equation:

2N₂  + 5O₂   →  2N₂O₅

Now we will compare the moles of N₂O₅ with oxygen.

                 N₂O₅          :           O₂

                     2            :             5

                    12.99      :         5/2×12.99 = 32.48 mol

Mass of oxygen:

Mass = number of moles × molar mass

Mass = 32.48 mol × 32 g/mol

Mass = 1039.36 g

4)

Given data:

Number of moles of benzene = 0.103 mol

Mass of carbon dioxide = ?

Solution:

Chemical equation:

2C₆H₆  + 15O₂   →  12CO₂ + 6H₂O

Now we will compare the moles of N₂O₅ with oxygen.

                  C₆H₆         :           CO₂

                     2            :             12

                    0.103      :         12/2×0.103 = 0.618 mol

Mass of carbon dioxide:

Mass = number of moles × molar mass

Mass = 0.618 mol × 44 g/mol

Mass = 27.192 g

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3 years ago
How many moles of al is needed to replace all the iron from 5.6 moles of fe2o3
Arte-miy333 [17]
Necesito los puntos es urgente
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3 years ago
Water is dripping into a bucket at a rate of 51 drops per minute. if each drop has a volume of 0.050 milliliters, what volume of
serious [3.7K]

112.2 milliliters volume of water will drip into the bucket in 44 minutes.

<h3>What is volume?</h3>

How much space an object or substance takes up. • Measured in cubic meters (m3), liters (L) & milliliters (mL).

Total drop = Drops per minute X time

= 51 drops per minute X 44 minutes

=2244 drop

Volume of water will drip into the bucket in 44 minutes

=Total drop X Volume of each drop

=0.050 milliliters X 2244 drop

=112.2 milliliters

Hence, 112.2 milliliters volume of water will drip into the bucket in 44 minutes.

Learn more about volume here:

brainly.com/question/10904074

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8 0
2 years ago
In a particular titration experiment a 30.0 ml sample of an unknown hcl solution required 25.0 ml of 0.200 m naoh for the end po
Nikitich [7]
The balanced equation for the acid base reaction is as follows
NaOH + HCl ---> NaCl + H₂O
stoichiometry of NaOH to HCl is 1:1
the number of NaOH moles reacted - 0.200 mol/L x 0.0250 L = 0.005 mol
according to molar ratio
number of NaOH moles reacted = number of HCl moles reacted 
therefore number of HCl moles - 0.005 mol 
volume of 30.0  mL contains 0.005 mol
therefore 1000 mL contains - 0.005 mol / 0.030 L = 0.167 M
concentration of HCl is 0.167 M
5 0
3 years ago
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