Among the choices, the polyatomic ion is only the third choice, NH4+ where it is composed of nitrogen one atom of nitrogen and 4 atoms of hydrogen. Choice 2 is a monoatomic atom being composed only of calcium. Then, the first and fourth choices are not ions because they are not charged.
1. True
2. False
3. False
4. True
5. True
6. True
7. All of the above
8. According to their reactivity with other substances
9. Standard temp and pressure
10. Flush your eyes in the eye flush for 15-20 minutes
Answer:
The mass ratio of oxygen rounded to the nearest whole no. 3 : 2
Explanation:
According to Law of Multiple proportion when two elements combine to make two or more different compounds, the mass ratio of the two element in the first compound, when divided by the mass ratio of the second compound , form a simple whole number ratio.
Compound A contains 1.34 g of sulfur for every 0.86 g of oxygen

Compound B contains 11.63 g of sulfur for every 10.49 g of oxygen

Ratio of oxygen in each compound
always put the larger number over the smaller number.

Answer: 1.36 M
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

where,
n = moles of solute
To calculate the moles, we use the equation:
moles of solute= 

The balanced reaction between barium hydroxide and perchloric acid:

To calculate the concentration of acid, we use the equation given by neutralization reaction:

where,
are the n-factor, molarity and volume of acid which is 
are the n-factor, molarity and volume of base which is 
We are given:

Putting values in above equation, we get:

Thus the concentration of the acid is 1.36 M
Answer:
i think the answer is c hoped this helped
Explanation: