Answer:
i am unique and have a specific number in the periodic table
Answer:
No photoelectric effect is observed for Mercury.
Explanation:
From E= hf
h= Plank's constant
f= frequency of incident light
Threshold Frequency of mercury= 435×10^3/ 6.6×10^-34 × 6.02×10^23
f= 11×10^14 Hz
The highest frequency of visible light is 7.5×10^14. This is clearly less than the threshold frequency of mercury hence no electron is emitted from the mercury surface
Answer:
19.8% of Nitrogen
Explanation:
In the Al(NO₃)₃ there are:
1 atom of Al
3 atoms of N
And 9 atoms of O
The molar mass of Al(NO₃)₃ is:
1 Al * (26.98g/mol) = 26.98g/mol
3 N * (14g/mol) = 42g/mol
9 O * (16g/mol) = 144g/mol
26.98 + 42 + 144 = 212.98g/mol
We can do a conversion using these molar masses to find the mass of nitrogen is the sample, that is:
2.57g * (42g/mol / 212.98g/mol) =
0.51g N
Percent composition of nitrogen is:
0.51g N / 2.57g * 100
= 19.8% of Nitrogen
You can put a known amount sodium into some sort of time release mechanism such as a pill made from soluble material. Then you can place the sodium into a calorimeter with a known mass of water and record the temperature change the water undergoes during the reaction. Then you can use the equation q(water)=m(water)c(water)ΔT to find the amount of heat absorbed by the water. since the amount of heat absorbed by the water is the amount of heat released from the sodium, q(sodium)=-q(water). Than you can use the equation q(sodium)=m(sodium)c(sodium)ΔT and solve for c(sodium)
I hope this helps and feel free to ask about anything that was unclear in the comments.
Answer:
Fr
Explanation:
Francium (Fr) has the lowest ionization energy, with a value of 4.0727eV. This ionization energy increases as one advances in a period, being greater in the group of nonmetals.
