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3 years ago

What is evidence of the dynamo theory?

1 answer:

3 0

Dynamo theory makes certain predictions. One is that a dynamo-induced magnetic field can exist only where a molten core exists within a fast-spinning planet. Small celestial bodies, such as Mars and the asteroids, long ago lost their heat, which shuts down the necessary convection near their cores. Venus is large enough to have retained its heat, but it spins very slowly, reducing the motion of its core and weakening the field. Mercury, which is too small to retain its primordial heat, does have a magnetic field as a result of its extreme inclination, which is allowed for in dynamo theory.

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Calculate [H3O+] and [OH−] for each of the following solutions at 25 ∘C given the pH.<br> pH= 2.89

dimaraw [331]

Answer: The value of $[H_{3}O^{+}]$ is 0.0012 M and $[OH^{-}]$ is $1.02 \times 10^{-14}$ .

Explanation:

pH is the negative logarithm of concentration of hydrogen ion.

It is given that pH is 2.89. So, the value of concentration of hydrogen ions is calculated as follows.

$pH = - log [H^{+}]\\2.89 = - log [H^{+}]\\conc. H^{+} = 0.0012 M$

The relation between pH and pOH value is as follows.

pH + pOH = 14

0.0012 + pOH = 14

pOH = 14 - 0.0012 = 13.99

Now, pOH is the negative logarithm of concentration of hydroxide ions.

Hence, $[OH^{-}]$ is calculated as follows.

$pOH = - log [OH^{-}]\\13.99 = - log [OH^{-}]\\conc. OH^{-} = 1.02 \times 10^{-14} M$

Thus, we can conclude that the value of $[H_{3}O^{+}]$ is 0.0012 M and $[OH^{-}]$ is $1.02 \times 10^{-14}$ .

6 0

3 years ago

Why do foods and fuels have chemical potential energy?

Ainat [17]

Fuels are burned to produce energy, and your body breaks down the food to produce nutrients for your body.

6 0

3 years ago

Read 2 more answers

Write the half-reactions as they occur at each electrode and the net cell reaction for this electrochemical cell containing indi

AlexFokin [52]

Explanation:

The given cell reaction is as follows.

$In(s)| In^{3+}(aq) || Cd^{2+}(aq) | Cd(s)$

Hence, reactions taking place at the cathode and anode are as follows.

At anode ; Oxidation-half reaction : $In(s) \rightarrow In^{3+}(aq) + 3e^{-}$ ...... (1)

At cathode; Reduction-half reaction : $Cd^{2+}(aq) + 2e^{-} \rightarrow Cd(s)$ ....... (2)

Hence, balance the half reactions by multiplying equation (1) by 2 and equation (2) by 3.

Therefore, net cell reaction is as follows.

$2In(s) \rightarrow 2In^{3+}(aq) + 6e^{-}$

$3Cd^{2+}(aq) + 6e^{-} \rightarrow 3Cd(s)$

Net reaction: $2In(s) + 3Cd^{2+}(aq) \rightarrow 2In^{3+}(aq) + 3Cd(s)$

Thus, we can conclude that the overall cell reaction is as follows.

$2In(s) + 3Cd^{2+}(aq) \rightarrow 2In^{3+}(aq) + 3Cd(s)$

4 0

3 years ago

When 16 g of methane (CH4) and 32 g of oxygen (O2) reacted to produce carbon dioxide and water, 11 g of carbon dioxide was produ

Aliun [14]

Answer:

Percent yield = 50%

Explanation:

Given data:

Mass of CH₄ = 16 g

Mass of O₂ = 32 g

Mass of CO₂ = 11 g

Percent yield of CO₂ = ?

Solution:

Chemical equation:

CH₄ + 2O₂ → CO₂ + 2H₂O

Number of moles of CH₄:

Number of moles = mass/ molar mass

Number of moles = 16 g /16 g/mol

Number of moles = 1 mol

Number of moles of O₂:

Number of moles = mass/ molar mass

Number of moles = 32 g /32 g/mol

Number of moles = 1 mol

Now we will compare the moles of CO₂ with both reactant.

O₂ : CO₂

2 : 1

1 : 1/2×1= 0.5 mol

CH₄ : CO₂

1 : 1

Number of moles of CO₂ produced by oxygen are less so it will limiting reactant.

Theoretical yield:

Mass of CO₂:

Mass = number of moles × molar mass

Mass = 0.5 mol × 44 g/mol

Mass = 22 g

Percent yield:

Percent yield = actual yield / theoretical yield × 100

Percent yield = 11 g/ 22 g × 100

Percent yield = 50%

3 0

3 years ago

Which process takes place in both plant and animal cells? Conversion of solar energy Cellular respiration Formation of glucose P

Vitek1552 [10]

Answer:

Cellular Respiration

Explanation:

6 0

3 years ago