Found the choices. Pls see attachment.
The statements that explains this phenomenon are:
1) DNA contains adenine as one of its nitrogenous bases.
2) DNA has a double-stranded structure that ensures an accurate mechanism of duplication.
Potassium oxide: K₂O.
There's no need for prefixes since K₂O is an ionic compound.
<h3>Explanation</h3>
Find the two elements on a periodic table:
- Potassium- K- on the left end of period four.
- Oxygen- O- near the right end of periodic two.
Elements on the bottom-left corner of the periodic table are metals. Those on the top-right corner are nonmetals.
- Potassium is a metal,
- Oxygen is a nonmetal.
A metal and a nonmetal combine to form an ionic compound. Potassium oxide is likely to be an ionic compound. It contains two types of ions:
- Potassium ions: Potassium is group 1 of the periodic table. It is an alkaline metal. Like other alkaline metals such as sodium Na, potassium K tends to lose one electron and form ions of charge +1 in compounds. The ion would be K⁺.
- Oxide ions from oxygen: Oxygen is the second most electronegative element on the periodic table. It tends to gain two electrons and form the oxide ion
when it combines with metals.
The two types of ions carry opposite charges. They shall pair up at a certain ratio such that they balance the charge on each other. The charge on each ion is twice that on a 
ion. Each would pair up with two . Hence the subscript in the formula: 
.
There are two classes of compounds:
- Covalent compounds, which need prefixes, and
- Ionic compounds, which need no prefix.
Prefixes are needed only in covalent compounds. For instance in the covalent compound carbon dioxide 
, the prefix di- indicates that there are two oxygen atoms in the formula . However, there's no need for prefix in ionic compounds such as 
.
Ethane is an alkane. Methane is also an alkane and is considered to be the simplest alkane. The difference is ethane has only 2 carbon. That carbon has 6 hydrogen attached to it. So what we do is we multiply the moles of ethane by the number of hydrogen (by dimension analysis) resulting to 82.68 moles H.
Answer : The correct match is:
1 positive charge = 1 negative charge
2 positive charges = 2 negative charges
3 positive charges = 3 negative charges
Explanation :
As we now that there are three subatomic particles which are protons, electrons and neutrons.
The protons and neutrons are located inside the nucleus and electrons are located around the nucleus.
The protons are positively charged, the electrons are negatively charged and neutrons are neutral.
As we know that all the things are made up of charges and opposite charges attract to each other.
In a neutral atom, the positive charges and negative charges are balanced in an object. That means, in neutral atom the number of positive charges are equal to the negative charges.
So we can say that:
1 positive charge = 1 negative charge
2 positive charges = 2 negative charges
3 positive charges = 3 negative charges
The hydrate form of CuSO4 has 5 water molecules (CuSO4-5H20) copper (II) Sulfate pentahydrate or commonly known as blue vitriol.
To solve, the following molar masses are to be known.
CuSO4.5H2O (hydrate) - 249.7g/mole
CuSO4 (anhydrous) -159.6g/mole
Also there molar ratio of the hydrate and CuSO4 is 1.
the mass of the hydrate is to be divided by the molar mass of the hydrate then multiplied by the ratio (1) to get the moles of hydrate and multiplied by the molar mass of the anhydrous to get the mass in grams.
moles = (100g/249.7)*1 = 0.4 moles hydrate
grams = 0.4*159.6 = 64.9 grames hydrate
