Adding and subtracting with scientific notation may require more care, because the rule for adding and subtracting exponential expressions is that the expressions must havelike terms<span>. Remember that to be </span>like terms<span>, two expressions must have exactly the same base numbers to exactly the same powers. Thinking about decimal arithmetic, the requirement that we have the same powers makes sense, because that guarantees that all of the place values are lined up properly.</span>
Answer:
81 °C
Explanation:
This is a calorimetry question so a few things you will need for this. The calorimetry equation q=mcΔT & the specific heat of water (4.2J/g•°C). Other definitions are:
q = heat added/released by a sample
m = mass of sample
c=specific heat of sample
ΔT = change in temperature
from here we can rearrange the equation to state:
q/(mc) = ΔT
1200J/((20.0g)(4.2J/g•°C)) = ΔT
14°C = ΔT
If the starting temperature was 95.0°C and we know that the temperature was cooled by 14°C then the final temperature of the water would be 81.
Carbon and silicon have same number of valance electrons which is 4 electrons
Now, Barium is a 2nd group element. So, it has two valance electrons.
Silicon is a 16th group element and it has 4 valance electrons as does the carbon. This is because they both stay in the same group in the periodic table.
Neon is a noble gas which has 8 valance electrons and stays in the 18th group.
Therefore, carbon and silicon have same number of valance electrons which is 4 electrons.
<h3>What are Valence electrons ?</h3>
The electrons in an atom's outermost shell, or energy level, are called valence electrons. For instance, the valence electrons of oxygen are six, with two in the 2s subshell and four in the 2p subshell.
- The number of valence electrons for neutral atoms is the same as the number of the atom's main group. A periodic table element's column can be used to determine its main group number. For instance, carbon, which belongs to group 4, has four valence electrons. Group 6 oxygen contains six valence electrons.
Learn more about Valence electrons here:
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LiOH is going to neutralize the acid because it’s a base
