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slamgirl [31]
3 years ago
14

Which geologic time did humans exist​

Chemistry
1 answer:
masha68 [24]3 years ago
8 0

<h2><u>PLEASE MARK BRAINLIEST!</u></h2>

It is believed that, 66 million years ago, the first human lived. This is according to fossil. It is thought that, after the Cretaceous–Paleogene extinction [the extinction of dinosaurs and 3/4 of plant and animal life], the first humans appeared.

I hope this helps!

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Which of the following actions does not require power
Kitty [74]

Answer:

Eating an apple

Explanation:

No electricity

4 0
3 years ago
Phosphorus-32 (32P) is an isotope that is commonly used for medical and biological research. Phosphorus-32 has a half-life of 14
Pachacha [2.7K]

The activity of the sample when it was shipped from the manufacturer is 4.54 mCi

<h3>How to determine the number of half-lives that has elapsed </h3>

From the question given above, the following data were obtained:

  • Time (t) = 48 hours
  • Half-life (t½) = 14.28 days = 14.28 × 24 = 342.72 hours
  • Number of half-lives (n) =?

n = t / t½

n = 48 / 342.72

n = 0.14

<h3>How to determine the activity of the sample during shipping </h3>
  • Number of half-lives (n) = 0.14
  • Original activity (N₀) = 5.0 mCi
  • Activity remaining (N) =?

N = N₀ / 2ⁿ

N = 5 / 2^0.14

N = 4.54 mCi

Thus, the activity of the sample during shipping is 4.54 mCi

Learn more about half life:

brainly.com/question/2674699

5 0
3 years ago
Is the answer B? Help
Masja [62]

Answer:

A

Explanation:

Hmm, so we have the following in the diagram

Pt(s)

Cl2(g)

Ag(s)

NaCl(aq)

AgNO3(aq)

Pt 2+, 4+, 6+  Though it states Pt is inert

Cl 2-

Ag 1+

Na 1+

NO3-

Anode definition: the positively charged electrode by which the electrons leave an electrical device.

Electrode definition: a conductor through which electricity enters or leaves an object, substance, or region.

Cations attracted to cathode pick up electrons

Anions attracted to anode release electrodes+

Reduction at Cathode (red cat gain of e)

Oxidation at Anode (ox anode loss of e)

So from the diagram we can see that the charge is being generated through the 2 metal plates.

So the answer is A, the anode material is Pt and the half reaction is 2Cl- = Cl2 + 2e-

7 0
3 years ago
is the process through which offspring are produced. A. Heredity B. Reproduction C. Conservation D. Vaccination
Dominik [7]
It is called Reproduction 
6 0
3 years ago
Read 2 more answers
A train that is accelerating at 5m/s² down the tracks and crashes into a car. If the train weighs 20,000kg, how much force does
iragen [17]

Answer:

100,000 N

Explanation:

Force, F = mass, m × acceleration, a

⇒F = ma

m= 20, 000kg

a = 5m/s²

∴ F = 5 × 20,000 = 100,000N

3 0
2 years ago
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