<span>You can answer this question by getting the atomic number and atomic mass of Oxygen from a periodic table. There you will find that the atomic number is 8, that means, by definition, that it has 8 protons. This is, because atomic number is defined as the number of protons of an element. Given that the atom is neutral, that implies that the atoms have the same number of electrons than protons. So you already know that the oxygen atoms has 8 protons and 8 electrons. The number of neutrons can vary, which is what defines the isotopes. Given that the atomic mass of oxygen is 15.999, that means that most atoms of oxygen has 8 neutrons (8 protons +8 neutrons = 16 atomic mass). But you can not be sure that a specific atom of oxygen has 8 neutrons, nevertheless, given that the other options are discarded (because they do not have 8 protons and 8 electrons), the only correct answer is the option A. 8 protons, 8 electrons, and 8 neutrons.</span>
Answer:
0.88 g
Explanation:
Using ideal gas equation to calculate the moles of chlorine gas produced as:-

where,
P = pressure of the gas = 805 Torr
V = Volume of the gas = 235 mL = 0.235 L
T = Temperature of the gas = ![25^oC=[25+273]K=298K](https://tex.z-dn.net/?f=25%5EoC%3D%5B25%2B273%5DK%3D298K)
R = Gas constant = 
n = number of moles of chlorine gas = ?
Putting values in above equation, we get:

According to the reaction:-

1 mole of chlorine gas is produced when 1 mole of manganese dioxide undergoes reaction.
So,
0.01017 mole of chlorine gas is produced when 0.01017 mole of manganese dioxide undergoes reaction.
Moles of
= 0.01017 moles
Molar mass of
= 86.93685 g/mol
So,

Applying values, we get that:-

<u>0.88 g of
should be added to excess HCl (aq) to obtain 235 mL of
at 25 degrees C and 805 Torr.</u>
NaHCO₃ + HCl → NaCl + H₂O + CO₂
<u>Explanation:</u>
NaHCO₃ + HCl → NaCl + H₂O + CO₂
When Sodium bi carbonate (NaHCO₃) reacts with hydrochloric acid (HCl), it forms table salt (NaCl), water ( H₂O ) and Carbon di oxide (CO₂) gas is evolved.
Here base reacts with acid to form salt and it is the neutralization reaction.
5 atoms is in 2CaCO3
Element: 1 atom
Compounds: 2+ atoms
Answer: D
Explanation:
Weight by definition is mass multiplied by the acceleration of gravity. So, weight is the force of gravity