Answer:
Error of parallax it usually occurs when the cylinder is above or below the eye level,and thus resulting in differences In reading the millimeters
<span>Molecular compounds, which are represented by molecules, are usually made of non-metals only (or of metalloids and non-metals). Ionic compounds, which are represented by formula units, are made of metals and non-metals.
More detail if you're interested: Molecules and formula units are the representative particles for molecular and ionic compounds, respectively. By that I mean, one unit of a molecular compound is a molecule...a bundle of atoms covalently bonded that exists separately from all the other molecules. One unit of an ionic compound is a formula unit. A formula unit is a representation of the compound's formula. For example, the formula unit of NaCl is one Na^+1 ion and one Cl^-1 ion. The formula unit of AlCl3 is one Al^+3 ion and three Cl^-1 ions. Ionic compounds don't have separate bundles of atoms like molecular compounds do, so the formula unit is just the smallest number of ions that it takes to represent the formula. </span>
<span><u><em>Answer:</em></u>
combustion reaction
<u><em>Explanation:</em></u>
In chemistry, a <u>combustion reaction</u> is defined as a reaction between an oxidant and any compound that leads to the production of another compound along with a huge amount of heat.
<u>Now, let's check the reaction given:</u>
C</span>₃H₈<span> + 5 O</span>₂<span> --> 3 CO</span>₂<span> + 4 H</span>₂O<span>
<u>The oxidant</u> is oxygen gas
<u>The compound reacting</u> is propane
<u>The compound produced</u> is carbon dioxide along with water vapor and heat
Therefore, the given reaction is a combustion reaction
Hope this helps :)</span>
When we go to periodic table, Sulfur is
an element that has 16 protons and 16 electrons.
when there is 18 electrons, with number of two electrons more than protons. This makes it an ion and
the ion has a -2 charge.
So when there is16 protons, 18 neutrons, and 18 electrons the symbol is S⁻².
The neutrons have no charge but they add only mass to the
elements. So when there is 16 neutrons, it doesn't change the symbol of ion.
