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ira [324]
3 years ago
14

Why are numbers placed before the elements and molecules in achemical equation?​

Chemistry
1 answer:
Neko [114]3 years ago
7 0

Answer:

the are coefficients for the atom. the tell how many there are.

Explanation:

they tell you how many atoms there are of its type.

ex. 4 C²H³. there are 4 of the c² and h³ (couldn't find a way to use subscript so used the power signs to show.)

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Convert 12 kcal to joules
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Answer:

50241.6

Explanation

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3 years ago
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Oxidation/reduction (redox) reactions like this: 2H2(g) + O2(g) ⇒ 2H2O(l) will occur spontaneously. To make the reaction proceed
igor_vitrenko [27]

The process is called electrolysis.

3 0
3 years ago
Using the equations 2 Sr(s) + O₂ (g) → 2 SrO (s) ∆H° = -1184 kJ/mol SrO (s) + CO₂ (g) → SrCO₃ (s) ∆H° = -234 kJ/mol CO₂ (g) → C(
kkurt [141]

<u>Answer:</u> The \Delta H^o_{rxn} for the reaction is 72 kJ.

<u>Explanation:</u>

Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.

According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.

The given chemical reaction follows:

2SrCO_3(s)\rightarrow 2Sr(s)+2C(s)+3O_2(g)      \Delta H^o_{rxn}=?

The intermediate balanced chemical reaction are:

(1) 2Sr(s)+O_2(g)\rightarrow 2SrO(s)    \Delta H_1=-1184kJ

(2) SrO(s)+CO_2(g)\rightarrow SrCO_3(s)     \Delta H_2=-234kJ      ( × 2)

(3) CO_2(g)\rightarrow C(s)+O_2(g)     \Delta H_3=394kJ    ( × 2)

The expression for enthalpy of the reaction follows:

\Delta H^o_{rxn}=[1\times (\Delta H_1)]+[2\times (-\Delta H_2)]+[2\times (\Delta H_3)]

Putting values in above equation, we get:

\Delta H^o_{rxn}=[(1\times (-1184))+(2\times -(-234))+(2\times (394))]=72kJ

Hence, the \Delta H^o_{rxn} for the reaction is 72 kJ.

4 0
3 years ago
A boron atom has ____ electrons at the first energy level and ____ electrons at the second energy level.
mylen [45]

Answer: A boron atom has 2 electrons at the first energy level and 3 electrons at the second energy level.

5 0
3 years ago
Which scientist performed the cathode ray experiment leading to the discovery of electrons
SVETLANKA909090 [29]

The scientist that performed the cathode ray experiment leading to the discovery of electrons is J.J. Thomson.

<h3>What is a cathode ray?</h3>

A cathode ray is a tube that contains negatively charged electrode( that is the cathode) which emits electrons when heated at a low pressure.

The cathode ray was used by the scientist, J.J. Thomson to find the ratio of charge to mass (e/m) of the electrons.

Therefore, the scientist that performed the cathode ray experiment leading to the discovery of electrons is J.J. Thomson.

Learn more about electrons here:

brainly.com/question/11316046

#SPJ1

6 0
2 years ago
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