Answer:
Only to elements are gases at room temperature and standard pressure.
Fluorine and chlorine.
Explanation:
The group 17 is called halogen.
There are five elements in halogen group.
All halogens required one electrons to complete the octet and to get the noble gas electronic configuration.
All halogen elements have seven valance electrons.
Halogen elements:
Fluorine, chlorine, Bromine, iodine and astatine
Fluorine is gas at room temperature which s 25°C and standard pressure which is 1 atm.
It is present in the from of F₂.
Chlorine is also gas at room temperature and standard pressure.
It is present in the from of Cl₂.
The bromine is liquid under these condition.
Iodine and astatine are solids.
As we move down the group their melting and boiling points increases.
Answer:
The correct answer is 0.36 mol
Explanation:
First we have to calculate the molecular weight (Mw) of H₃BO₃ from the molar masses of the elements:
Mw(H₃BO₃)= 3 x Molar mass H + Molar mass B + (3 x Molar mass O)
= 3 x 1 g/mol + 10.8 g/mol + (3 x 16 g/mol)
= 61.8 g/mol
The molecular weight indicates that there are 61.6 grams per mol of substance. The scientist has 22.5 g, thus we can calculate the number of moles of H₃BO₃ by dividing the mass into the molecular weight as follows:
Number of moles of H₃BO₃ = mass/Mw= (22.5 g)/(61.8 g/mol) = 0.36 mol
There are 0.36 mol of H₃BO₃ in 750.0 mL of solution.
Answer:
5.733 days
Explanation:
To convert from minuets to days we must first convert minuets to hours. To do this we divide by 60 since there are 60 minuets in one hour.
8255 min ÷ 60 = 137.6 hr
Now that we have the amount of hours we can convert to days by dividing by 24 since there are 24 hours in one day.
137.6 hr ÷ 24 = 5.733 days
(2.03x10^22)/(6.02x10^23) = .033721 mol Li
I hope this helps, if not, i am sorry
Answer:
chemical energy into thermal energy
Explanation:
The reaction taking place is as follows
2C₂H₂ + 5O₂ = 4CO₂ + 2H₂O + Heat
In this reaction bonds present in acetylene is broken and new bond present in water and carbon dioxide are formed . In the whole process of bond breaking and bond formation , there is net loss of energy and that energy is released as heat energy .
Thus we can say that in the whole process , chemical energy is converted into heat energy .
