A feature that an iron metal has is a sea of electrons
Answer:
8.73
Explanation:
when you are adding or subtracting numbers, the sigfig (significant figure) is based on how many numbers after the decimal. with this info, we can see that 15.67 has 2 sigfigs and 6.943 has 3 sigfigs. when you subtract normally, you would get 8.727, which has 3 sigfigs, so you would round the last 7 up to get 8.73 with 2 sigfigs!
also it is to 2 sigfigs because we know that we go by the least number of sigfigs. hope this helped!
Answer:
Methods for determining or delivering precise volumes include volumetric pipets and pycnometers; less precise methods include burets, graduated cylinders, and graduated pipets. In this experiment, you will measure masses and volumes to determine density. Four different metal cylinders are investigated.
Explanation:
Answer: I believe the answer is d) the rock crumbles at an ocean ridges
Explanation:
First, we need to get the value of Ka:
when Ka = Kw / Kb
we have Kb = 1.8 x 10^-5
and Kw = 3.99 x 10^-16 so, by substitution:
Ka = (3.99 x 10^-16) / (1.8 x 10^-5) = 2.2 x 10^-11
by using the ICE table :
NH4+ + H2O →NH3 + H+
intial 0.013 0 0
change -X +X +X
Equ (0.013-X) X X
when Ka = [NH3][H+] / [NH4+]
by substitution:
2.2 x 10^-11 = X^2 / (0.013 - X) by solving this equation for X
∴X = 5.35 x 10^-7
∴[H+] = X = 5.35 x 10^-7
∴PH = - ㏒[H+]
= -㏒(5.35 x 10^-7)
= 6.27