Answer:
A) The number of atoms in a grain of iron is most similar to the number of meters between Earth and Vega.
The options attached to the question are missing, but out of the numbers presented in the options, 10¹⁷ is closest to 10¹⁸.
B) The mass of a grain of iron is approximately (9 × 10⁻⁵) g
Explanation:
The options attached to the question are missing, after searching online, the image of the question was obtained, but it won't be attached to this solution in order not to violate the community guidelines and lead to deletion of answer.
But, out of the numbers presented in the options, 10¹⁷ is closest to 10¹⁸, hence, the number of atoms in a grain of iron is most similar to the number of meters between Earth and Vega.
The second part of the question asks for the approximate mass of a grain of iron.
1 atom of iron has a mass of (9 × 10⁻²³) g
1 grain of iron has about (1 × 10¹⁸) atoms of iron.
So, the mass of a grain of iron = (9 × 10⁻²³) × (1 × 10¹⁸) = (9 × 10⁻⁵) g
Hope this Helps!!!
Answer:
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Lemon juice in its natural state is acidic with a pH of about 2, but once metabolized it actually becomes alkaline with a pH well above 7
<h2 /><h2>Hope it was helpfulll </h2>
<h2>Answer:</h2>

<h2>Explanations</h2>
The complete balanced equation for the given reaction is expressed as;

Given the following parameters
Mass of CH4 = 5.90×10^−3 g = 0.0059grams
Determine the moles of methane

According to stoichimetry, 1 mole of methane produces 2 moles of water, hence the moles of water required will be:

Determine the mass of water produced

Therefore the mass of water produced from the complete combustion of 5.90×10−3 g of methane is 1.33 * 10^-2grams
Explanation:
In a voltaic cell, oxidation reaction occurs at anode whereas reduction reaction occurs at the cathode.
Hence, the half-cell reaction taking place at anode and cathode will be as follows.
At anode (Oxidation) :
...... (1)
At cathode (Reduction) : 
So, in order to balance the half cell reactions, we multiply reduction reaction by 3. Hence, reduction reaction equation will be as follows.
........ (2)
Therefore, overall reaction will be sum of equations as (1) + (2). Thus, net reaction equation is as follows.
<span>Volume increases at the same rate as temperature.</span>