3 years ago

An atom contains 31 protons,39neutrons and 31 electrons.Identify the mass number of this atom

Chemistry

1 answer:

AlladinOne [14]3 years ago

5 0

Answer:

Atomic mass =70

Explanation:

Mass number is total protons +total neutrons

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Answer:

The pan will be the same temperature as the stove.

Explanation:

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The decomposition of N I 3 to form N 2 and I 2 releases − 290.0 kJ of energy. The reaction can be represented as 2N I 3 (s)→ N 2

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Answer:

The change in enthaply when 10.0 g of nitrogen triiodide decomposes is -3.67 kJ.

Explanation:

$2NI_3 (s)\rightarrow N_2 (g)+3 I_2 (g), \Delta H_{rxn} =-290.0 kJ$

Enthalpy of the reaction when 2 moles of nitrogen triiodide decomposed = $\Delta H_{rxn}$

$\Delta H_{rxn} = -290.0 kJ$

Enthalpy of the reaction when 1 moles of nitrogen triiodide decomposed :

$\Delta H=\frac{\Delta H_{rxn}}{2}=\frac{-290.0 kJ}{2} =-145.0 kJ$

Mass of nitrogen triiodide decomposed = 10.0 g

Moles of nitrogen triiodide = $\frac{10.0 g}{395 g/mol}=0.02532 mol$

Change in enthaply when 0.02532 moles of nitrogen triiodide decomposed:

$\Delta H\times 0.02532=-145 kJ\times 0.02532=-3.67 kJ$

3 0

3 years ago

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Fofino [41]

Hmm, welll I think it’s heterogeneous

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3 years ago

The density of a pure substance is its mass per unit volume. The density of cresol has been measured to be 1024 g/L . Calculate

Ierofanga [76]

Answer: The mass of 405 ml of cresol is 415 grams

Explanation:

Density is defined as the mass contained per unit volume.

$Density=\frac{mass}{volume}$

Given : Density of cresol = 1024 g/L

Volume of cresol = 405 ml = 0.405 L ( 1L=1000ml)

Putting in the values we get:

$1024g/L=\frac{mass}{0.405L}$

$mass=1024g/L\times 0.405L=415g$

Thus mass of 405 ml of cresol is 415 grams

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3 years ago

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Harrizon [31]

Answer:

sweating

Explanation:

why do I need 20 words

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3 years ago

An atom contains 31 protons,39neutrons and 31 electrons.Identify the mass number of this atom​

An atom contains 31 protons,39neutrons and 31 electrons.Identify the mass number of this atom