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2 years ago

13

Suppose that, from measurements in a microscope, you determine that a certain bacterium covers an area of 1.50μm2. Convert this

to square meters

1 answer:

Salsk061 [2.6K]2 years ago

8 0

You determine that a certain layer of graphene covers an area of 1.50μm2. ... Convert this to square meters. 1.

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If you weigh 100 kg, how much would you weigh if all the water were removed from your body? A65 kg B45 kg C50 kg D35 kg

Mekhanik [1.2K]

Answer:

B. 45k

The human body is about 60 to 70% water.

(:

5 0

2 years ago

Carbon dating of small bits of charcoal used in cave paintings has determined that some of the paintings are from 10000 to 30000

Andru [333]

The age of painting was determined from the decay kinetics of the radioactive Carbon -14 present in the painting sample.

Given that the half life of Carbon-14 is 5730 years.

Radioactive decay reactions follow first order rate kinetics.

Calculating the decay constant from half life:

λ $= \frac{0.693}{t_{1/2} }$

= $\frac{0.693}{5730 yr}$ = $1.21*10^{-4}yr^{-1}$

Setting up the radioactive rate equation:

$ln\frac{A_{t} }{A_{0} } =-kt$

Where $A_{t} = Activity after time t = 0.80microCi$

$A_{t} = initial activity = 6.4microCi$

k = decay constant = $1.21*10^{-4}yr^{-1}$

$ln\frac{0.80uCi}{6.4uCi} =-(1.21*10^{-4}yr^{-1})t$

ln 0.125 = $-(1.21*10^{-4}yr^{-1})t$

-2.079= $-(1.21*10^{-4}yr^{-1})t$

t= $\frac{2.07944}{1.21*10^{-4} } yr$

= 17185 years

t = 17185 years

Therefore age of the painting based in the radiocarbon -14 dating studies is 17185 years

6 0

2 years ago

An ion has 24 protons and 19 electrons. Write the symbol for this ion.

Lerok [7]

Answer:

+5

Explanation:

it hs 5 more protons thant electrons, so it has a positive charge of 5

5 0

2 years ago

Lithium chloride forms three hydrates. They are LiCl.H2O, LiCl.2H2O and LiCl.3H2O.

Stels [109]

Answer:

The answer is LiCl.2H2O

Explanation:

Li=7

Cl=35.5

O=16

LiCl.H2O

7+35.5+16+2

60.5

%comp=60.5/78.5×100

22.9

LiCl.2H20

7+35.5+2(2+16)

42.5+36

78.5

%comp=36/78.5×100

45.9

LiCl.3H20

7+35.5+3(2+16)

42.5+54

96.5

54/96.5×100

56.0

7 0

2 years ago

Liquid X is known to have a higher surface tension and higher viscosity than Liquid Y Use these facts to predict the result of b

creativ13 [48]

Answer:

O FX will be greater than FY

Explanation:

<em>Surface tension</em> can be defined as the force required to stretch one film of a given fase (usually with liquids).

This required force is proportional to the liquid's surface tension. This means that the higher the surface tension, the higher the required force to stretch it is.

5 0

2 years ago