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12345 [234]
3 years ago
11

¡¡¡PLEASE HELP!!! I'm stuck on a question..

Chemistry
1 answer:
Reptile [31]3 years ago
7 0

 The half  life  of uranium- 238  is

 4.46 x10^9  years


 Explanation

Half life  is the time  taken for  the  radioactivity  of   a isotope  to fall  to half  its  original  value.

The  original   mass  of uranium-238  is  4.0 mg

  Half  of original  mass of uranium  = 4.0  mg /2 = 2.0  mg

since  it  take 4.46  x 10^ 9 years  for  the sample   to half  the half life of uranium -238 = 4.46 x10^9 years

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Yes chloride is an element.... hope this helps!!
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What is a polyprotic buffer?
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Buffers - mixtures of conjugate acid and conjugate base at ±1 pH unit from pH = pKa. Resistant to changes in pH in response to small additions of H+ or OH-. ... Polyprotic acids - dissociation of each H+ can be treated separately if the pKa values are different
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3 years ago
I need chemistry help! How would I set up these problems?
Bond [772]

Answer: -

1) 8.33 minutes

2) 118.39 in/ s

180.43 m/min

10.83 km/ hr

Explanation: -

Speed of light = 3 x 10⁸ m/s

Distance of the earth from the sun= 93 million miles

We know 1 million = 1,000,000

Also 1 mile = 1609 m

Distance of the earth from the sun= 93 million miles

= 93,000,000 miles.

= 1.5 x 10^{11} m

Time taken = \frac{Distance}{Speed}

= \frac{1.5 x [tex] 10^{11} m}{3 x 10⁸ m/s} [/tex]

= 500 s

= 500/ 60

= 8.33 minutes

2) Distance = 1 mile = 63360 inches

Time taken = 8.92 min

= 8.92 x 60

= 535.2 s

Speed = \frac{distance}{time}

= \frac{63360 inches}{535.2 s}

= 118.39 in/ s

Distance = 1 mile = 63360 inches = 63360 x 2.54 cm = 63360 x 2.54 x 10^{-2} m

Time taken = 8.92 min

Speed = \frac{distance}{time}

= \frac{63360 x 2.54 x [tex] 10^{-2} m}{8.92 min} [/tex]

= 180.43 m/ min

1 m = 10⁻³ Km

1 min = 1/60 hour

1 m /min = 10⁻³ km/ \frac{1}{60 hour}

= 60/1000

=0.06 km/hr

180.43 m / min = 180 x 0.06 km / hr

= 10.93 km / hr

4 0
3 years ago
Mantle material rises in convection currents because heated materials becomes more dense
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Heated mater rises and cold mater sinks
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4 years ago
What is the hydrogen ion concentration of a solution with a pH 5? *
nekit [7.7K]

Answer:

In the same way, a solution with a pH of 5 contains 10-5mol/l of hydrogen ions, a solution with a pH of 6 contains 10-6mol/l of hydrogen ions, while the solution with a pH of 7 contains 10-7mol/l of hydrogen ions.

Explanation:

5 0
3 years ago
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