Answer:
b) 2.0 mol
Explanation:
Given data:
Number of moles of Ca needed = ?
Number of moles of water present = 4.0 mol
Solution:
Chemical equation:
Ca + 2H₂O → Ca(OH)₂ + H₂
now we will compare the moles of Ca and H₂O .
H₂O : Ca
2 : 1
4.0 : 1/2×4.0 = 2.0 mol
Thus, 2 moles of Ca are needed.
A gas with a vapor density greater than that of air, would be most effectively displaced out off a vessel by ventilation.
The two following principles determine the type of ventilation: Considering the impact of the contaminant's vapour density and either positive or negative pressure is applied.
Consider a vertical tank that is filled with methane gas. Methane would leak out if we opened the top hatch since its vapour density is far lower than that of air. A second opening could be built at the bottom to greatly increase the process' efficiency.
A faster atmospheric turnover would follow from air being pulled in via the bottom while the methane was vented out the top. The rate of natural ventilation will increase with the difference in vapour density. Numerous gases that require ventilation are either present in fairly low concentrations or have vapor densities close to one.
When 6.85×10⁵ cal is converted to kilojoules, the result obtained is 2866.04 KJ
<h3>Data obtained from the question </h3>
- Energy (cal) = 6.85×10⁵ cal
- Energy (KJ) =?
<h3>Conversion scale </h3>
1 cal = 0.004184 KJ
<h3>How to convert 6.85×10⁵ cal to kilojoules</h3>
1 cal = 0.004184 KJ
Therefore,
6.85×10⁵ cal = 6.85×10⁵ × 0.004184
6.85×10⁵ cal = 2866.04 KJ
Thus, 6.85×10⁵ cal is equivalent to 2866.04 KJ
Learn more about conversion:
brainly.com/question/2139943
The oxidation number of P in Mg3P2 is 3. When writing ionic compounds, you swap the oxidation numbers and add them as the subscript.
Answer:
- Compress
- Fixed
- Melts
- Melting Point
- Freezing Point
- High
- Crystalline
- Lattice
- Unit cell
- Amorphous solids
Explanation:
Solids tend to be dense and difficult to <u>compress.</u>
They do not flow or take the shape of their containers, like liquids do, because the particles in solids vibrate around <u>fixed</u> points.
When a solid is heated until its particles vibrate so rapidly that they are no longer held in fixed positions, the solid <u>melts</u>.
<u>Melting point</u> is the temperature at which a solid changes to a liquid. The melting and <u>freezing point</u> of a substance are at the same temperature.
In general, ionic solids tend to have relatively <u>high</u> melting points, while molecular solids tend to have relatively low melting points.
Most solids are <u>crystalline</u>
The particles are arranged in a pattern known as a crystal <u>lattice</u>
The smallest subunit of a crystal lattice is the <u>unit cell</u>
Some solids lack an ordered internal structure and are called <u>amorphous solids.</u>
