For for the formulas with the abbreviated names of the ions, you switch the exponents for each one, so for number 2 it would be Fe2O3 or for 6 it would be CaCl2
For the compounds, you take the abbreviated names of the ions from the periodic table and wherever the ion falls, that’s how many electrons it has and so it would need more ions to make the full shell, so for sodium chloride, since both need one, it would be NaCl or for tin (ll) fluoride, it would be SnF2
Answer:
- <u><em>Option D. qsys = - qsurr</em></u>
Explanation:
The symbol q is used to denote heat energy.
Considering positive the heat absorbed and negative the heat released:
- <em>qsys</em> is the heat absorbed by the systme
- <em>qsurr</em> is the heat absorbed by the surroundings
When the system does not do work on or receive work from the surroundings, the first law of thermodynamics states that:
- <em>qsys </em>+ <em>qsurr</em> = 0
From which:
- <em>qsys = - qsurr ← </em>answer
That is the option D.
That means that, the heat abosorbed by the system (if <em>qsys</em> is positive) equals the heat released by the surroundings, or the heat released by the system (if <em>qsys</em> is negative) equals the heat absorbed by the surroundings.
In general, bonds with an electronegativity difference of 0-0.5 are nonpolar covalent, bonds with an EN difference of 0.5-2.0 are covalent, and anything above 2.0 is considered ionic.
To determine the bond types of the pairs of elements, we will need their EN values. We can subtract their EN values to find their EN difference.
H and Br: 2.96-2.20=0.76
Therefore a bond between H and Br would be moderately polar covalent.
Cl and F: 3.98-3.16=0.82
Therefore this bond is moderately polar covalent.
K and Cl: 3.16-0.82=2.34
Therefore this bond is ionic.
Li and O: 3.44-0.98=2.46
Therefore this bond is ionic.
Br and Br: Because these are the same element, meaning that they have the same EN value, we automatically know that their EN difference would be zero. Therefore, this bond is very covalent.
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Answer:
Explanation:
1 Calorie = 4184 Joules
450 Calories = 450 x 4184 J
= 188.28 x 10⁴ J
3.5 x 10⁶ joules
4184 joules = 1 Calorie
3.5 x 10⁶ joules = 836.52 Calories.