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3 years ago

Which of the following is the best description of an elment

Chemistry

2 answers:

Readme [11.4K]3 years ago

4 0

Answer:

Explanation:

atoms join together to produce elements

Tresset [83]3 years ago

4 0

Answer:

An element is a substance whose atoms all have the same number of protons: another way of saying this is that all of a particular element's atoms have the same atomic number. Elements are chemically the simplest substances and hence cannot be broken down using chemical reactions.

Explanation:

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A. The sand and water together in the beaker is called a

Rina8888 [55]

Answer:

sand and water together in the beaker is called a mixture

3 0

3 years ago

One of the hazards of nuclear explosions is the generation of 90Sr andits subsequent incorporation in place of calcium in bones.

Illusion [34]

Explanation:

Initial mass of the isotope 90-Sr in baby= 1.00 μg

Formula used :

$N=N_o\times e^{-\lambda t}\\\\\lambda =\frac{0.693}{t_{\frac{1}{2}}}$

where,

$N_o$ = initial mass of isotope

N = mass of the parent isotope left after the time, (t)

$t_{\frac{1}{2}}$ = half life of the isotope = 28.1 years

$\lambda$ = rate constant

$N=N_o\times e^{-(\frac{0.693}{t_{1/2}})\times t}$

a) Time taken by the sample, t = 18 years

$N=1.00 \mu g\times e^{-\frac{0.693}{28.1 years}\times 18 years}$

$N = 0.6415 \mu g$

0.6415 μg will remain after 18 years.

b) Time taken by the sample, t = 70 years

$N=1.00 \mu g\times e^{-\frac{0.693}{28.1 years}\times 70 years}$

$N = 0.1779\mu g$

0.1779 μg will remain after 70 years.

3 0

3 years ago

Write the complete ionic equation for the reaction that takes place when aqueous solutions of strontium hydroxide and lithium ph

Nesterboy [21]

Answer : The net ionic equation will be,

$3Sr^{2+}(aq)+2PO_4^{3-}(aq)\rightarrow Sr_3(PO_4)_2(s)$

Explanation :

In the net ionic equations, we are not include the spectator ions in the equations.

Spectator ions : The ions present on reactant and product side which do not participate in a reactions. The same ions present on both the sides.

The given balanced ionic equation will be,

$3Sr(OH)_2(aq)+2Li_3PO_4(aq)\rightarrow 6LiOH(aq)+Sr_3(PO_4)_2(s)$

The ionic equation in separated aqueous solution will be,

$3Sr^{2+}(aq)+6OH^{-}(aq)+6Li^{+}(aq)+2PO_4^{3-}(aq)\rightarrow Sr_3(PO_4)_2(s)+6Li^+(aq)+6OH^{-}(aq)$

In this equation, $Li^+\text{ and }OH^-$ are the spectator ions.

By removing the spectator ions from the balanced ionic equation, we get the net ionic equation.

The net ionic equation will be,

$3Sr^{2+}(aq)+2PO_4^{3-}(aq)\rightarrow Sr_3(PO_4)_2(s)$

4 0

3 years ago

Three radioisotopes are being discussed in a chemistry class. Technetium-99m has a half-life of 6 hours. Rubidium-87 has a half-

suter [353]

B.)<span>A doctor would use technetium-99m because a short half-life indicates a quick measurement, and a geologist would use rubidium-87 because a longer half-life means that there is a longer time to measure old rock. </span>

3 0

3 years ago

Read 2 more answers

Which elements have 50protons

igomit [66]

Answer:

Tin (Sn) as in the periodic table the element tin has 50 protons

7 0

3 years ago

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