The atomic number is the number of protons an element has, protons are positively charged and electrons are negatively charged. All elements have no charge so the number of electrons will always equal the number of protons for an element so there are 6 electrons.
Answer:
177.1 L
Explanation:
The excersise can be solved, by the Ideal Gases Law.
P . V = n . R . T
In first step we need to determine the moles of gas:
We convert T° from, C° to K → 20°C + 273 = 293K
We convert P from mmHg to atm → 760 mmHg = 1atm
1Dm³ = 1L → 190L
We replace: 190 L . 1 atm = n . 0.082 . 293K
(190L.atm) / 0.082 . 293K = 7.91 moles.
We replace equation at STP conditions (1 atm and 273K)
V = (n . R .T) / P
V = (7.91 mol . 0.082 . 273K) / 1atm = 177.1 L
We can also make a rule of three:
At STP conditions 1 mol of gas occupies 22.4L
Then, 7.91 moles will be contained at (7.91 . 22.4) /1 = 177.1L
A rock is obviously more dense than a crumpled piece of paper of the same size. A styrofoam cup is less dense than a ceramic cup.
hope this helps if it do mark me as brainlest thank you !!
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1) Determine the rate constant for the reaction:
<span>k = (ln 2) / t_1/2 <--- I'll leave you to figure out how that came to be. Hint: use the integrate form of the first-order rate law </span>
<span>k = (ln 2) / 23.6 min </span>
<span>k = 0.02937 min^-1 <--- keep a few extra digits </span>
<span>1) use the integrated form of the first-order rate law: </span>
<span>ln A = -kt + ln A_o </span>
<span>ln A = - (0.02937 min^-1) (120 min) + ln 2.50 </span>
<span>ln A = -3.5244 + 0.91629 </span>
<span>ln A = -2.60811 </span>
<span>A = 0.07367 M <--- round off more as you see fit </span>
<span>Here's another way: </span>
<span>120 min / 23.6 min = 5.106383 half-lives </span>
<span>(0.5)^5.106383 = 0.02902856 <--- the decimal amount remaining after 5.106383 half-lives </span>
<span>0.02902856 x 2.50 M = the answer</span>
MnO2 is the formula for manganese (4) dioxide