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1 year ago

What is the number of protons plus the number of neutrons in the nucleus of an atom equivalent to?

Chemistry

1 answer:

Kryger [21]1 year ago

7 0

Answer:

Explanation:

b/c proton + neutron=mass number and

mass number - proton= neutron

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Butane C4H10 (g),(Hf = –125.7), combusts in the presence of oxygen to form CO2 (g) (Delta.Hf = –393.5 kJ/mol), and H2O(g) (Delta

shusha [124]

Answer: The enthalpy of combustion, per mole, of butane is -2657.4 kJ

Explanation:

The balanced chemical reaction is,

$2C_4H_{10}(g)+13O_2(g)\rightarrow 8CO_2(g)+10H_2O(g)$

The expression for enthalpy change is,

$\Delta H=[n\times H_f_{products}]-[n\times H_f_{reactants}]$

Putting the values we get :

$\Delta H=[8\times H_f_{CO_2}+10\times H_f_{H_2O}]-[2\times H_f_{C_4H_{10}+13\times H_f_{O_2}}]$

$\Delta H=[(8\times -393.5)+(10\times -241.82)]-[(2\times -125.7)+(13\times 0)]$

$\Delta H=-5314.8kJ$

2 moles of butane releases heat = 5314.8 kJ

1 mole of butane release heat = $\frac{5314.8}{2}\times 1=2657.4kJ$

Thus enthalpy of combustion per mole of butane is -2657.4 kJ

3 0

2 years ago

On average, Earth’s crust contains about 8.1% aluminum by mass. If a standard 12-ounce soft drink can contains approximately 15

MrMuchimi

Answer:

5400 cans

Explanation:

First we convert the total weight, 1 ton, to grams:

$1ton=1x10^{6}g$

Now we need to know the mass of aluminum:

$m_{Al}=\frac{10^{6}*8.1}{100} =81000g$

Now we make the relation between the mass of aluminum in 1 ton of the earth's crust and the mass of aluminum per can:

$n=\frac{81000g}{15g/can} =5400cans$

8 0

3 years ago

Which civilization formed a confederation thay may have impacted the us government

lana66690 [7]

Answer:

Anasazi

Explanation:

3 0

2 years ago

Use the tabulated half-cell potentials to calculate the equilibrium constant (K) for the following balanced redox reaction at 25

o-na [289]

The equation Eºcell = 0.0592/n logK must be used to find n and also Eºcell
2 Al(s) + 3 Mg2+(aq) → 2 Al3+(aq) + 3 Mg(s) Al3+ +3e- --> Al Eº = -1.66 V Mg2+ +2e- -->Mg Eº = -2.37V
To balance the equation, 6 moles of electrons must be transferred (2 Al and 3 Mg). This will be the value of n in the equation.
To find Eºcell, you need the reduction potentials which should be given in a table, and given above. Eºcell = -1.66 - (-2.37) = 0.71 V log K = Eºcell x n/0.0592 = 0.71 x 6/0.0592 log K = 71.95 K = 10^71.95 K = 1.1x10^72

6 0

3 years ago

The backbone of nucleic acids consists of

V125BC [204]

Answer:

c. a phosphodiester bond between the 3' and 5' hydroxyl groups of neighboring sugars

Explanation:

Phosphodiester bond is the bond which is formed between the hydroxyl group of one nucleotide to the phosphate group of the another nucleotide. These are ester bonds. These bonds are central to all the life which is in existence on Earth. These bonds forms the backbone of the strands of the nucleic acid.

The bond is formed by the linkage of 3' carbon atom of one of the sugar unit to the 5' carbon atom of the another succeeding sugar unit.

<u>Hence, the answer is:- c. a phosphodiester bond between the 3' and 5' hydroxyl groups of neighboring sugars</u>

4 0

2 years ago