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Slav-nsk [51]
3 years ago
9

How many mg of a 31-mg sample of calciul 47 remains after 45 days

Chemistry
2 answers:
Feliz [49]3 years ago
8 0
36 days is 8 half-life periods
mario62 [17]3 years ago
7 0
<span>36 days is 8 half-life periods</span>
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What are the common properties of the following element groups:
son4ous [18]

Answer:

Alkali and alkaline-earth cations are energetically stable with an empty valence shell. Atoms of alkali and alkaline-earth elements achieve octets after losing one (alkali) or two (alkaline-earth) electrons such that they minimize the potential energy of the system.

8 0
2 years ago
A person accidentally swallows a drop of liquid oxygen, O2(l), which has a density of 1.149 g/mL. Assuming the drop has a volume
nasty-shy [4]

Answer:

First, let's determine how many moles of oxygen we have.

Atomic weight oxygen = 15.999

Molar mass O2 = 2*15.999 = 31.998 g/mol

We have 3 drops at 0.050 ml each for a total volume of 3*0.050ml = 0.150 ml

Since the density is 1.149 g/mol,

we have 1.149 g/ml * 0.150 ml = 0.17235 g of O2

Divide the number of grams by the molar mass to get the number of moles 0.17235 g / 31.998 g/mol = 0.005386274 mol

Now we can use the ideal gas law. The equation PV = nRT where P = pressure (1.0 atm) V = volume n = number of moles (0.005386274 mol) R = ideal gas constant (0.082057338 L*atm/(K*mol) ) T = Absolute temperature ( 30 + 273.15 = 303.15 K)

Now take the formula and solve for V, then substitute the known values and solve.

PV = nRT V = nRT/P V = 0.005386274 mol * 0.082057338 L*atm/(K*mol) * 303.15 K / 1.0 atm V = 0.000441983 L*atm/(K*) * 303.15 K / 1.0 atm V = 0.133987239 L*atm / 1.0 atm V = 0.133987239 L

So the volume (rounded to 3 significant figures) will be 134 ml.

8 0
3 years ago
Read 2 more answers
For the chemical equation SO 2 ( g ) + NO 2 ( g ) − ⇀ ↽ − SO 3 ( g ) + NO ( g ) the equilibrium constant at a certain temperatur
MakcuM [25]

Answer:

Moles of NO₂ = 0.158

Explanation:

                         SO 2 ( g ) + NO 2 ( g ) ⇄  SO 3 ( g ) + NO ( g )

              According to the law of mass equation

                                     

                                       K_{c} = \frac{[SO_{3} ][NO]}{[SO_{2}][NO_{2}  ]}

                              ⇒   3.10 = \frac{(1.00)(1.00)}{(2.30) [NO_{2} ]}    At equilibrium [SO₃] = [NO]

                              ⇒ [NO₂] = \frac{1}{6.3}

                              ⇒ [NO₂] = 0.158

So. number of moles of NO₂ at equilibrium added = 0.158

8 0
3 years ago
What is frost action
attashe74 [19]
The weathering process caused by cycles of freezing and thawing of water in surface pores, cracks, and other openings



7 0
3 years ago
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At STP how many moles or helium would occupy a volume of 12 liters?
butalik [34]
1 mole ------------- 22.4 L ( at STP )
?? mole ---------- 12 L

12 x 1 / 22.4 => 0.5357 moles

hope this helps! 
5 0
3 years ago
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