Answer:
basic unit of le nervous system is ur nerves brother nah im jp ur brain bcs if u didnt have a brain u wouldnt feel anything :D
Explanation:
The nuclei of atoms also contain neutrons, which help hold the nucleus together. ... The total weight of an atom is called the atomic weight. It is approximately equal to the number of protons and neutrons, with a little extra added by the electrons.
The mass of a given atom, measured on a scale in which the hydrogen atom has the weight of one. Because most of the mass in an atom is in the nucleus, and each proton and neutron has an atomic weight near one, the atomic weight is very nearly equal to the number of protons and neutrons in the nucleus.
Answer:
its is letter c is your answer
Explanation:
I hope this help
Answer:
a. withdraws electrons inductively
b. donates electrons by hyperconjugation
c. donates electrons by resonance
d. withdraws electrons inductively
Explanation:
a. The bromide ion is a highly electronegative ion (in the halide series). Electronegative substituents on acids increase the acidity by inductive electron withdrawal method. The higher the electronegativity of a substance, the greater the acidity. The halogens have this order of electronegativity:
F > Cl > Br>I
b. The carboxyl groups have a stabilization of the sigma and pi bonds. This is achieved through a special delocalization of electrons. Because of the delocalization, hyperconjugation is the result effect.
c. The NHCH₃ group has a highly electonegative nitrogen atom that pulls the electron cloud towards itself. In this case, it withdraws electrons inductively. As a result, it donates electrons by resonance.
d. The OCH₃ group has a highly electonegative oxygen atom. This oxygen atom withdraws electron cloud towards itself. As a result, it withdraws electrons inductively.
To get the empirical formula, we need to know the ratio of the moles of both lead and sulfur.
First, lets get the mass of each:
mass of lead = mass of evaporating dish and lead - mass of empty dish
= <span>26.927 - 25.000 = 1.927 gm of lead (Pb)
mass of sulfur = mass of dish and lead sulfide - mass of dish and lead
= </span><span>27.485 - 26.927 = 0.558 gm of sulfur (S)
The next step is to get the number of moles in 1.927 gm of Pb and in 0.558 gm of S:
From the periodic table:
molar mass of lead = </span>207.2 gm<span>
molar mass of sulfur = 32 gm
number of moles = mass / molar mass
number of moles of Pb = 1.927 / 207.2 = </span>0.0093 moles<span>
number of moles of S = 0.558 / 32 = </span><span>0.0174 moles
The third step is to get the ratio between the moles by dividing the number of moles of each by the smaller of the two:
1 mole of Pb (</span>0.0093 / 0.0093) reacts with 0.0174 / 0.0093 = 1.99 (approximately 2 moles) of sulfur.
Final step is to write the empirical formula based on the ratio:
Lead sulfide compound is written as : PbS2
