Answer : The name of positive ion present in this sample is, hydronium ion.
Explanation :
For formation of a neutral ionic compound, the charges on cation and anion must be balanced.
The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Ion : An ion is formed when an atom looses or gains electron.
When an atom looses electrons, it will form a positive ion known as cation.
When an atom gains electrons, it will form a negative ion known as anion.
As per question, hydronium ion or hydrogen ion is having an oxidation state of +1 called as 
or 
cation and nitrate ion 
is an anion with oxidation state of -1.
Thus they combine and their oxidation states are exchanged and written in simplest whole number ratios to give neutral 
.
Hence, the name of positive ion present in this sample is, hydronium ion.
The grams of Na that are needed to complete to react with 40..0 g of O2 is calculated as below
find the moles of O2 used = mass/molar mass
= 40 g/32g/mol = 1.25 moles
write the reacting equation
4Na+ O2 = 2Na2O
by use of mole ratio between Na to O2 which is 4 :1
the moles of Na = 1.25 x 4 = 5 moles
mass of Na = mass x molar mass
= 5 moles x 23 g /mol= 115 moles
The population will get low because the food we eat is animals which is species then the animals that eat that prey will die off because that might be there only prey....then if more species is gone there will be nothing left
I Hope this helped
Answer:
B, 2.22×10^22 molecules
Explanation:
Given PV=nRT, n=PV/RT
n=103.7×1.0/8.314×(65+273.15)
= 0.0368858... moles
Given n= number of particles/avogadros number
number of particles=n×avogadros number
number of particles = 0.03688...×6.02x10^23
= 2.22×10^22 molecules
Combining oxygen gas and hydrogen gas to form liquid water is a chemical change. Pretty sure the rest are physical changes because a chemical change happens when a substance is altered completely. A physical change is when a substance keeps its components (I dunno what word to use) but just changes into a diferent shape. At least thats how my teacher explained it to me.
