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2 years ago

What element is stored in the shells and skeltyons of living organisims?

Chemistry

1 answer:

kykrilka [37]2 years ago

8 0

Answer:

carbon

Explanation:

Many organisms use carbon to make calcium carbonate, a building material of shells and skeletons. Other chemical processes create calcium carbonate in the water. The using up of carbon by biological and chemical processes allows more carbon dioxide to enter the water from the atmosphere.

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Which object forms when a supergiant runs out of fuel? a red giant a black hole a white dwarf a neutron star

NeTakaya

I believe the correct answer would be "neutron star"

5 0

2 years ago

Read 2 more answers

What is the [OH-] of a substance that has a pH of 11?

Deffense [45]

Answer:

0.001 M OH-

Explanation:

[OH-] = 10^-pOH, so

pOH + pH = 14 and 14 - pH = pOH

14 - 11 = 3

[OH⁻] = 10⁻³ ; [OH-] = 0.001 M OH-

6 0

2 years ago

Please and thank you!

Valentin [98]

Answer:

7.5 moles of O₂.

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

2KClO₃ —> 2KCl + 3O₂

From the balanced equation above,

2 moles of KClO₃ decomposed to produce 3 moles of O₂.

Finally, we shall determine the number of mole of O₂ produced by the decomposition of 5 moles of KClO₃. This can be obtained as follow:

From the balanced equation above,

2 moles of KClO₃ decomposed to produce 3 moles of O₂.

Therefore, 5 moles of KClO₃ will decompose to produce = (5 × 3)/ 2 = 7.5 moles of O₂.

Thus, 7.5 moles of O₂ were obtained from the reaction.

3 0

2 years ago

When a radioactive isotope releases an alpha particle, the atomic number of the atom is (2 points)

natali 33 [55]

When alpha decay takes place, two protons and two neutrons are forcefully ejected from the nucleus in a way that looks very similar to a Helium nucleus. This type of decay causes the atomic mass of the parent particle to drop by four (four particles lost), but the atomic number drops by only two (two protons lost). Therefore, your answer is C.

8 0

3 years ago

Read 2 more answers

Which balanced equation represents a redox reaction? a. AgNO3(aq) +NaCl(aq) →AgCl(s) +NaNO3(aq) b. H2CO3(aq) →H2O() + CO2(g) c.

Aleks [24]

Answer : The correct option is, (D) $Mg(s)+2HCl(aq)\rightarrow MgCl_2(s)+H_2(g)$

Explanation :

(A) $AgNO_3(aq)+NaCl(aq)\rightarrow AgCl(s)+NaNO_3(aq)$

This reaction is a double displacement reaction in which the cation and anion of two reactants are exchange their places to give two different products.

(B) $H_2CO_3(aq)\rightarrow H_2O(l)+CO_2(g)$

This reaction is a decomposition reaction in which the larger molecule decomposes to give two or more products.

(C) $NaOH(aq)+HCl(aq)\rightarrow NaCl(s)+H_2O(aq)$

This reaction is a neutralization reaction in which an acid and a base react to give a salt and water as a product.

(D) $Mg(s)+2HCl(aq)\rightarrow MgCl_2(s)+H_2(g)$

This reaction is a redox reaction in which the oxidation and reduction reaction occur simultaneously.

Oxidation reaction is the reaction in which a substance looses its electrons. In this oxidation state increases.

Reduction reaction is the reaction in which a substance gains electrons. In this oxidation state decreases.

In this reaction, magnesium shows oxidation due to change in oxidation number from (0) to (+2) and hydrogen shows reduction due to change in oxidation number from (-1) to (0).

Hence, the correct option is, (D)

7 0

2 years ago