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2 years ago

What can be concluded about the atom from knowing that oxygen 18 has an atomic number of 8?

2 answers:

7 0

<span>The atomic number of a neutral atom is equal to the number of protons and the number of electrons of the atom. The atomic weight meanwhile is equal to the sum of the number of protons and number of neutrons.Hence we can say that the number of protons is 8 and the number of neutrons is 10. </span>

RSB [31]2 years ago

5 0

hi............................

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If 200.0 g of copper(II) sulfate react with an excess of zinc metal, what is the theoretical yield of copper? 1.253 g 50.72 g 79

Helen [10]

1)we need a balanced equation: CuSO₄ + Zn ---> ZnSO₄ + Cu

2) we need to convert the grams of CuSO₄ to moles using the molar mass.

molar mass CuSO₄= 63.5 + 32.0 + (4 x 16.0)= 160 g/mol

$200.0 g CuSO_4 ( \frac{1 mol}{160 grams} )= 1.25 mol CuSO_4$

3) convert moles of CuSO₄ to moles of Cu

$1.25 mol CuSO_4 ( \frac{1 mol Cu}{1 mol CuSO_4} )= 1.25 mol Cu$

4) convert moles of Cu to grams using it's molar mass.

molar mass Cu= 63.5 g/mol

$1.25 mol (\frac{63.5 grams}{1 mol} )= 79.4 grams Cu$

I did it step-by-step as the explanation but you can do all of this in one step.

$200.0 g CuSO_4 ( \frac{1 mol CuSO_4}{160 g} ) ( \frac{1 mol Cu}{1 mol CuSO_4} ) ( \frac{63.5 grams}{1 mol Cu} )= 79.4 grams Cu$

4 0

2 years ago

Give a possible explanation for the relative amounts of the isometric methyl nitrobenzoates formed in the nitration reaction. Co

vovikov84 [41]

Answer:

The electrophilic aromatic substitution reaction nitration is used to nitrate methyl benzoate and acetanilide with a nitronium ion. Crystallization was used to purify the product. The melting point was used to determine its purity and the regiochemistry of the products.

Explanation:

Methyl m-Nitrobenzoate is formed in this

reaction rather that ortho/para isomers

because of the ester group of your starting

product of methylbenzoate. The functional

group of ester is a electron withdrawing group

causing nitrobenzene (N02) to become in the

meta position. Thus N02 is a deactivating

group causing itself to be a meta director.

Basically you must look at the substituents

that are attached to your starting benzene ring

in order to figure out whether your reaction

with be ortho/para directors or meta

directors. If the substituents are electron

withdrawing groups then you will be left with

meta as your product but if your substituents

are electron donating groups then your

product will be ortho/para.

4 0

2 years ago

Driving cars lowers the pH of the oceans by _______.

Anna [14]

Correct answer: a. releasing CO2 that dissolves and forms acid in the oceans

The fuels used in automobiles release gases like carbon dioxide, carbon monoxide, oxides of nitrogen and sulfur. Carbon dioxide when dissolved in water forms carbonic acid. So, when the usage of cars is high, these emissions of carbon-dioxide into the atmosphere increase and this leads to the lowering of pH of the oceans as the carbon dioxide present in higher amounts in to atmosphere diffuses into the oceanic waters and form carbonic acid which makes the ocean slightly acidic.

$CO_{2}(g) + H_{2}O (l) H_{2}CO_{3}(aq)$

6 0

2 years ago

Read 2 more answers

A sample of an ideal gas occupies 2.78 x 10^3 mL at 25°C and 760 mm Hg.

iris [78.8K]

Answer: It will occupy $4.45\times 10^3ml$ at the same temperature and 475 mm Hg.

Explanation:

Boyle's Law: This law states that pressure is inversely proportional to the volume of the gas at constant temperature and number of moles.

$P\propto \frac{1}{V}$ (At constant temperature and number of moles)

$P_1V_1=P_2V_2$ (At constant temperature and number of moles)

where,

$P_1$ = initial pressure of gas = 760 mm Hg

$P_2$ = final pressure of gas = 475 mm Hg

$V_1$ = initial volume of gas = $2.78\times 10^3ml$

$V_2$ = final volume of gas = ?

Putting in the values:

$760mm Hg\times 2.78\times 10^3ml=475 mm Hg\times V_2$

$V_2=4.45\times 10^3ml$

Thus it will occupy $4.45\times 10^3ml$ at the same temperature and 475 mm Hg

5 0

2 years ago

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Stephanie has been doing research on how petroleum is formed. She says that oxygen must be present while the tiny plants and ani

madreJ [45]

Answer:

No, Stephanie is incorrect. Formation of petroleum cannot take place under the presence of oxygen.

Explanation:

Since, the petroleum is fossil product. Fossil fuel are formed under high pressure and temperature with absence of oxygen for longer period. so the way she is performing is completely incorrect. With the presence of oxygen in no way petroleum will be formed. The temperature and pressure should be in different combination for the formation of the petroleum. Along with the layers of sediments to maintain the pressure is required.

5 0

2 years ago

Read 2 more answers