Answer:
DE2
Explanation: for every one D+2 you need two E-1 because +2=-2
Data:
M (molarity) = ? (M or Mol/L)
m (mass) = 13.50 g
V (volume) = 250 mL → 0.25 L
MM (Molar Mass) of Lead(IV) Nitrate

Pb = 1*207 = 207 amu
N = (1*14)*4 = 14*4 = 56 amu
O = (3*16)*4 = 48*4 = 192 amu
------------------------------------
MM of

= 207+56+192 = 455 g/mol
Formula:

Solving:




Answer:
<span>
B. 0.119 M</span>
E = hc/(lamda)
The lamda symbol is wavelength, which this site does not have. I can represent it with an "x" instead.
Plancks constant, h = 6.626×10^-32 J·s
Speed of light, c = 3.00×10^8 m/s
The energy must be greater than or equal to 1×10^-18 J
1×10^-18 J ≤ (6.626×10^-32 J·s)*(3.0×10^8 m/s) / x
x ≤ (6.626×10^-32 J·s)*(3.0×10^8 m/s) / (1×10^-18 J)
x ≤ 1.99×10^-7 m or 199 nm
The wavelength of light must be greater than or equal to 199 nm
<h2>
Hello!</h2>
The answer is: Charle's Law.
<h2>
Why?</h2>
The law that states that the volume and absolute temperature of a fixed quantity of gas (ideal gas) are proportional under constant pressure is the Charle's Law, also known as the law of volumes.
The law describes how a gas kept under constant pressure tends to expand when the temperature increases and it's described by the following equation:

Where,

Also, to describe the relationship between two differents volumes at different temperatures, we have:

Where,

Have a nice day!
Answer:
No. 3 lithium
Explain that lithium has 3 protons and 3 electrons. There are 2 electrons on the first energy level and 1 electron on the second
No. 4 Hydrogen (H) and helium (He) have a valence shell containing one and two electrons respectively. They make up the first period (row) of the periodic table. Their valence electron/s are in the first energy level (n=1) , as is denoted by 1s1 and 1s2 .
<em>That</em><em>'</em><em>s</em><em> </em><em>all</em><em> </em><em>i</em><em> </em><em>dont</em><em> </em><em>know</em><em> </em><em>if</em><em> </em><em>this</em><em> </em><em>is</em><em> </em><em>right</em><em> </em><em>though</em><em>.</em><em> </em>