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fomenos
3 years ago
6

How many elements have been discovered so far by scientists ​

Chemistry
1 answer:
Inessa [10]3 years ago
6 0

Answer:

118 elements have been discovered so far

Explanation:

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Chromium-51 is a radioisotope that is used to assess the lifetime of red blood cells The half-life of chromium-51 is 27.7 days.
8090 [49]

Answer:

11.9g remains after 48.2 days

Explanation:

All isotope decay follows the equation:

ln [A] = -kt + ln [A]₀

<em>Where [A] is actual amount of the isotope after time t, k is decay constant and [A]₀ the initial amount of the isotope</em>

We can find k from half-life as follows:

k = ln 2 / Half-Life

k = ln2 / 27.7 days

k = 0.025 days⁻¹

t = 48.2 days

[A]  = ?

[A]₀ = 39.7mg

ln [A] = -0.025 days⁻¹*48.2 days + ln [39.7mg]

ln[A] = 2.476

[A] = 11.9g remains after 48.2 days

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8 0
3 years ago
The approximately 20 basic building blocks of protein are called
Grace [21]
Amino acids join end to end to form proteins since they are monomers.
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8 0
3 years ago
Read 2 more answers
Bbbbbbbbbbbbbbbbbbbb
padilas [110]
Lol now way he answers this
8 0
3 years ago
If 16g of <img src="https://tex.z-dn.net/?f=CH_%7B4%7D" id="TexFormula1" title="CH_{4}" alt="CH_{4}" align="absmiddle" class="la
sammy [17]

43.56 grams of  are produced if 16g of  CH4 reacts with 64g of O2.

Explanation:

Balance equation for the reaction:

CH4 + 2O2⇒ CO2 +2H2O

Data given : mass of CH4 =16 grams  atomic mass = 16.04 grams/mole

                    mass of water 36 gram  atomic mass = 18 grams/moles

                   mass of CO2=?                atomic mass = 44.01 grams/mole

number of moles = \frac{mass}{atomic mass of one mole}    equation 1

number of moles in CH4

   n = \frac{16}{16.04}

       = 0.99 moles

Since combustion is done in presence of oxygen hence it is an excess reagent and methane is limiting reagent so production of CO2 depends on it.

From the equation

1 mole of CH4 gave 1 mole of CO2

O.99 moles of CH4 will give x moles of CO2

\frac{1}{1} = \frac{x}{0.99}

x = 0.99 moles of carbon dioxide

grams of CO2 = number of moles x atomic mass

                         = 0.99 x 44.01

                          = 43.56 grams of CO2 is produced.

4 0
3 years ago
Which statement would support a merit of the Bronsted-Lowry base theory has over the Arrhenius base theory?
butalik [34]

Answer:

Explanation:

Bronsted Base is an H+ acceptor

No good answer Bronstead base does not accept hydroxide or electrons

5 0
3 years ago
Read 2 more answers
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