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Lemur [1.5K]
2 years ago
12

(pls help!) What mass of oxygen atoms is required to react completely with 30 u of hydrogen atoms?​

Chemistry
2 answers:
Nataly [62]2 years ago
6 0
  • 2H_2+O_2—»2H_2O

One mole Hydrogen need 1/2mol O_2 .

Moles of Hydrogen

  • 30u/1u
  • 30mol

Moles of O_2

  • 30/2
  • 15mol

Nikolay [14]2 years ago
6 0

\qquad\qquad\huge\underline{{\sf Answer}}

Let's get to the reaction first ~

\qquad \qquad \rm 2H_2 + O_2  \rightarrow 2H_2O

Here, we can infer that if we need 1 mole oxygen gas to react with 2 moles Hydrogen gas.

So, the number of Oxygen gas molecules we need to react should be half the number of Hydrogen gas molecules.

Number of Hydrogen gas molecules is :

\qquad \sf  \dashrightarrow \:  \dfrac{30}{2}

\qquad \sf  \dashrightarrow \:  15

Number of Oxygen gas molecules needed is :

\qquad \sf  \dashrightarrow \:   \dfrac{15}{2}

Number of Oxygen atoms needed :

\qquad \sf  \dashrightarrow \:   \dfrac{15}{2}  \times 2

\qquad \sf  \dashrightarrow \:  {15} \: atoms

One atom of Oxygen weight 16 u, so 15 atoms weight ~

\qquad \sf  \dashrightarrow \:  {15} \times 16

\qquad \sf  \dashrightarrow \:  240 \: u

So, we need 240 u of Oxygen atoms to react completely with 30 u of Hydrogen atoms.

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Answer:

Therefore, the specific heat capacity of the iron is 0.567J/g.°C.

<em>Note: The question is incomplete. The complete question is given as follows:</em>

<em>A 59.1 g sample of iron is put into a calorimeter (see sketch attached) that contains 100.0 g of water. The iron sample starts off at 85.0 °C and the temperature of the water starts off at 23.0 °C. When the temperature of the water stops changing it's 27.6 °C. The pressure remains constant at 1 atm. </em>

<em> Calculate the specific heat capacity of iron according to this experiment. Be sure your answer is rounded to the correct number of significant digits</em>

Explanation:

Using the formula of heat, Q = mc∆T  

where Q = heat energy (Joules, J), m = mass of a substance (g)

c = specific heat capacity (J/g∙°C), ∆T = change in temperature (°C)

When the hot iron is placed in the water, the temperature of the iron and water attains equilibrium when the temperature stops changing at 27.6 °C. Since it is assumed that heat exchange occurs only between the iron metal and water; Heat lost by Iron = Heat gained by water

mass of iron  = 59.1 g, c = ?, Tinitial = 85.0 °C, Tfinal = 27.6 °C

∆T = 85.0 °C - 27.6 °C = 57.4 °C

mass of water = 100.0 g, c = 4.184 J/g∙°C, Tinitial = 23.0 °C, Tfinal = 27.6 °C

∆T = 27.6°C - 23.0°C = 4.6 °C

Substituting the values above in the equation; Heat lost by Iron = Heat gained by water

59.1 g * c * 57.4 °C  = 100.0 g * 4.184 J/g.°C * 4.6 °C

c = 0.567 J/g.°C

Therefore, the specific heat capacity of the iron is 0.567 J/g.°C.

5 0
2 years ago
The ka of hf is 6.8 x 10-4. what is the ph of a 0.35 m solution of hf?
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When the reaction equation is:

HF ↔ H+   +   F-

and when the Ka expression
= concentration of products/concentration of reactions

so, Ka = [H+][F-]/[HF]

when we assume:

[H+] = [F-] = X

and [HF] = 0.35 - X

So, by substitution:

6.8 x 10^-4 = X^2 / (0.35 - X) by solving for X

∴ X = 0.015 M

∴[H+] = X = 0.015

when PH = -㏒[H+]

∴PH = -㏒0.015

        = 1.8
6 0
3 years ago
Zn + O2= ZnO<br><br> How many moles of zinc are needed to make 500. g of zinc oxide?​
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Answer:

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Explanation:

2zn + o2 = 2zno

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nzno=500/(16x2+65)= 5.15 moles

-> nzn = 5.15 x 2 ÷ 2 = 5.15 moles

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Which cell organelle is like the construction site, where proteins are built? Which cell organelle packages and transports the p
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Explanation:

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Answer:

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