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3 years ago

8

Which element is reduced in the following reaction: 2Mg+O₂ → 2MgO if Mg goes from 0 to +2 and O goes from 0 to -2?

1 answer:

Lyrx [107]3 years ago

8 0

Answer:

O.

Explanation:

The element which is oxidized is the element that losses electrons and its oxidation state be more positive.

The element which is reduced is the element that gain electrons and its oxidation state be more negative.

<em> O goes from 0 to -2, so, it is the element that is reduced.</em>

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Which of these describes an exothermic reaction?

Paul [167]

A nswer: -

C. Energy is released by the reaction

Explanation:-

An exothermic reaction is one in which during the progress of the reaction heat is evolved.

So energy is released by the reaction.

It cannot be created as energy is neither created nor destroyed as per the Law of conservation of energy. Energy is not transferred either.

The energy released during the progress of the reaction originates from the chemical bonds of the reactants as they break during their conversion into products.

3 0

3 years ago

Read 2 more answers

Which of the following below is the complete ionic equation of the reaction: Calcium nitrate and sodium sulfide solutions react

3241004551 [841]

To find the net ionic equation we must first write the balanced equation for the reaction. We must bear in mind that the reagents Ca(NO3)2 and Na2S are in the aqueous state and as product we will have CaS in the solid state, since it is not soluble in water and NaNO3 in the aqueous state.

The balanced equation of the reaction will be:

$Ca(NO_3)_{2(aq)}+Na_2S_{(aq)}\rightarrow CaS_{(s)}+2NaNO_{3(aq)}$

Ca(NO3)2(aq) + → Ca(aq) + 2Na(s)NO3Now, c(aq)ompounds in the aqueous state can be written in their ionic form, so the reaction will transform into:Na2S +

$Ca_{(aq)}^{2+}+2(NO_3)_{(aq)}^-+2Na_{(aq)}^++S_{(aq)}^{2-}\operatorname{\rightarrow}CaS_{(s)}+2Na_{(aq)}^++2NO^-_{3(aq)}$

So, the answer will be option A

5 0

1 year ago

A brick has a mass of 4.0 kg and the Earth has a mass of 6.0 × 1027 g. Use this information to answer the questions below. Be su

Vedmedyk [2.9K]

Answer:

a) $2.4\times 10^{24} kg$ is the mass of 1 mole of bricks.

b) $2.5\times 10^3$ moles of bricks have a mass equal to the mass of the Earth.

Explanation:

a) Mass of brick = 4.0 kg

1 mole = $N_A=6.022\times 10^{23}$ particles/ atoms/molecules

Mass of $N_A$ bricks :

$=6.022\times 10^{23}\times 4.0 kg=2.4088\times 10^{24} kg\approx 2.4\times 10^{24} kg$

$2.4\times 10^{24} kg$ is the mass of 1 mole of bricks.

b)

Mass of the Earth = M = $6.0\times 10^{27} kg$

Mass of 1 mole of brick = m= $2.4\times 10^{24} kg$

Let the moles of brick with equal mass of the Earth be x.

$m\times x=M$

$x=\frac{M}{m}=\frac{6.0\times 10^{27}kg}{2.4\times 10^{24} kg}=2.5\times 10^3$

$2.5\times 10^3$ moles of bricks have a mass equal to the mass of the Earth.

7 0

4 years ago

Match the following with their correct molecular weight. 2-butanone Propyl acetate 4-methyl-2-pentanone Butyl acetate Methanol E

Hatshy [7]

Answer:

2-butanone = 72.11 g/mol (option F)

Propyl acetate = 102.13 g/mol (option C)

4-methyl-2-pentanone = 100.16 g/mol (option D)

Butyl acetate = 116.16 g/mol (option B)

Methanol = 32.04 g/mol (option E)

Ethanol = 46.07 g/mol (option A)

Explanation:

Step 1: Data given

Molar mass of C = 12.01 g/mol

Molar mass of H = 1.01 g/mol

Molar mass of O = 16.00 g/mol

Step 2:

2-butanone = C4H8O

⇒ 4*12.01 + 8*1.01 + 16.00 = 72.11 g/mol (option F)

Propyl acetate = C5H10O2

⇒ 5*12.01 + 10*1.01 + 2*16.00 = 102.13 g/mol (option C)

4-methyl-2-pentanone = C6H12O

⇒ 6*12.01 + 12*1.01 + 16.00 = 100.16 g/mol (option D)

Butyl acetate = C6H12O2

⇒ 6*12.01 + 12*1.01 + 2*16.00 = 116.16 g/mol (option B)

Methanol = CH3OH = CH4O

⇒ 12.01 + 4*1.01 + 16.00 = 32.04 g/mol (option E)

Ethanol = C2H5OH = C2H6O

⇒ 2*12.01 + 6*1.01 + 16.00 = 46.07 g/mol (option A)

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3 years ago

Zachary adds 9.7 g to 1.114 g.<br> How many significant figures should his answer have?

makvit [3.9K]

Always use least amount of sig figs possible. So this 9.7 would be (answer): 2 sig figs

5 0

3 years ago