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Svetach [21]
3 years ago
7

1.25 Quiz: Impacts of Humans

Chemistry
2 answers:
Ket [755]3 years ago
8 0
I think any of the two,it can a or d
vekshin13 years ago
5 0
Pretty sure it’s A and D
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Pls answer with a passion and a goal of smartness
Svetach [21]

Answer:

b

Explanation:

I used my passion and skill for learning to do a quick google search :P

7 0
3 years ago
Read 2 more answers
A chemist wishing to do an experiment requiring 47-Ca2+ (half-life = 4.5 days) needs 5.0 μg of the nuclide. What mass of 47-CaCO
NARA [144]

Answer:

5.8μg

Explanation:

According to the rate or decay law:

N/N₀ = exp(-λt)------------------------------- (1)

Where N = Current quantity,  μg

            N₀ = Original quantity, μg

             λ= Decay constant day⁻¹

              t =  time in days

Since the half life is 4.5 days, we can calculate the  λ from (1) by  substituting N/N₀ = 0.5

0.5 = exp (-4.5λ)

ln 0.5  = -4.5λ

-0.6931 = -4.5λ

λ =   -0.6931 /-4.5

  =0.1540 day⁻¹

Substituting into (1)  we have :

N/N₀ = exp(-0.154t)----------------------------- (2)

To receive 5.0 μg of the nuclide with a delivery time of 24 hours or 1 day:

N = 5.0 μg

N₀ = Unknown

t = 1 day

Substituting into (2) we have

[5/N₀]   = exp (-0.154 x 1)

    5/N₀        = 0.8572

N₀  =  5/0.8572

     =    5.8329μg

    ≈     5.8μg

The Chemist must order 5.8μg  of 47-CaCO3

6 0
3 years ago
If 5.0 moles of C3H8 react, how many molecules of water are formed?
artcher [175]
Balance Chemical Equation for combustion of Propane is as follow,

                         C₃H₈  +  5 O₂    →    3 CO₂  +  4 H₂O

According to equation,

              1 mole of C₃H₈ on combustion gives  =  4 moles of H₂O
So,
        5 moles of C₃H₈ on combustion will give  =  X moles of H₂O

Solving for X,
                                    X  =  (5 mol × 4 mol) ÷ 1 mole

                                    X  =  20 moles of H₂O

Calculating number of molecules for 20 moles of H₂O,
As,
                        1 mole of H₂O contains  =  6.022 × 10²³ molecules
So,
                20 moles of H₂O will contain  =  X molecules

Solving for X,
                                 X  =  (20 mole × 6.022 × 10²³ molecules) ÷ 1 mol

                                 X  =  1.20 ×10²⁵ Molecules of H₂O
8 0
3 years ago
The change in time for the first quarter is
Flura [38]

Answer:

2.34

Explanation:

6 0
3 years ago
Read 2 more answers
At sea level, a kilogram welghs approximately<br> 2 pounds<br> 10 pounds<br> 5 pounds<br> 1 pound
Vedmedyk [2.9K]

Answer:

1 kilogram weight at sea level would be the equivalent of  2 pounds.

Explanation:

5 0
3 years ago
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