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Assoli18 [71]
4 years ago
9

What does the number next to isotopes signify?

Chemistry
2 answers:
elixir [45]4 years ago
3 0
It is an approximation of its mass number. Each isotope of an element has a different mass number.
erma4kov [3.2K]4 years ago
3 0
<span>The number next to the isotope is the mass number- They all have different masses because they have different numbers of neutrons, but the same amount of protons (Remember protons + neutrons = mass)</span>
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HELP
snow_lady [41]

Explanation:

a chemical reaction that absorbs energy is known to be endothermic since heat is being taken in by the reaction. The value of the transition state would be 150 because you have to subtract the product's enthalpy and the reactant's enthalpy to obtain it. A positive value for the transition state also corroborates that the reaction is endothermic.

5 0
3 years ago
Stoichiometry is best defined as the
Oxana [17]

Stoichiometry is “quantitative relationship” among the “reactants” and the “products” in a “chemical reaction”.

<u>Explanation</u>:  

In stoichiometry “stoicheion” means element and “metron” means measure in Greek. The stoichiometric calculation depends upon “stoichiometric coefficients” in a “chemical equation” which can be explained as the “number of moles” of each substance (reactants or products). Stoichiometric calculation is done as follows:

For example reaction between nitrogen and hydrogen to form ammonia as

\mathrm{N}_{2}(\mathrm{g})+3 \mathrm{H}_{2}(\mathrm{g}) \longrightarrow 2 \mathrm{NH}_{3}(\mathrm{g})

Here stoichiometric coefficients show that “one molecule of nitrogen” reacts with “three molecules of hydrogen” to form “two molecules of ammonia”. Multiplying Avogadro number 6.022 \times 10^{23} to no of molecules in equation:

\text { For } \mathrm{N}_{2}: 1 \times 6.022 \times 10^{23}=1 \mathrm{mol}

\text { For } 3 \mathrm{H}_{2}: 3 \times 6.022 \times 10^{23}=3 \mathrm{mol}

\text { For } 2 \mathrm{NH}_{3}: 2 \times 6.022 \times 10^{23}=2 \mathrm{mol}

Taking molar masses into consideration:  

\text { For } \mathrm{N}_{2}: 1 \times 28.0=28.0 \mathrm{gm}

\text { For } 3 \mathrm{H}_{2}: 3 \times 2=6.0 \mathrm{gm}

\text { For } 2 \mathrm{NH}_{3}: 2 \times 17=34 \mathrm{gm}

Hence balanced equation gives stoichiometric coefficients which gives proportion by moles.

8 0
3 years ago
C3H8 (g)+ 502 (g)  3CO2 (g) + 4 H2O (g) + 531 kcal
aniked [119]

Answer:

Exotérmica.

Explanation:

¡Hola!

En este caso, dado que la mayoría de reacciones de combustión son exotérmicas, al generar calor en los productos, es posible inferir que esta reacción, referida a la combustion de metano es exotérmica debido a lo anteriormente mencionado, ya que el término de energía de reacción, 531 kcal, está al lado de los productos, lo que quiere decir que es energía generada.

¡Saludos!  

5 0
3 years ago
Helppppppppp!!!!!!!!!
Ksivusya [100]

The answer is C.) Pair it with a hydrogen half-cell

6 0
3 years ago
How many mm are equal to 21 L. How many mg are equal to 9 g. How many grams are equal to 400 kg
liberstina [14]
<span>How many mm are equal to 21 L? 

1 L = </span>1000000 mm

Convert:-

1000000 × 21 = <span>21000000

21 l = </span><span>21000000 mm

</span><span>How many mg are equal to 9 g?

1 g = 1000 mg

Convert:-

9 </span>× 1000 = 9000

9 g = 9000 mg
8 0
4 years ago
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