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3 years ago

PLEASE HELP DUE TODAY

Chemistry

1 answer:

11111nata11111 [884]3 years ago

5 0

Formula mass, molar mass and Avagadro's number.

Explanation:

number of atoms in a compound can be calculated by knowing the molar mass of the compound or element, the result will be multiplied by avagadro's number (6.022*10^23)

1 mole of a substance is equal to Avagadro number of atoms.

If the number of moles is known of a compound or element its molar mass can be calculated as:

n= Weight of the compound/element given/ molecular weight of the same.

formula mass is the mass of compound ie chemical compound formed with different molecules. its mass is calculated by adding the molar masses of all the elements taking part in its assembly.

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D) +1

timurjin [86]

Answer:

I guess letter A

Explanation:

but the real number of oxidation of PO-

p=1

O= -2

can you explain, how can I answer this question?

I know how to get the oxidation but the problem is there nothing to the options.

6 0

2 years ago

You placed 43.1 g of an unknown metal at 100 °C into a coffee cup calorimeter that contained 50.0 g of water that was initially

nika2105 [10]

Answer :

(a) The heat released by the metal is -312.48 J

(b) The specific heat of the metal is $0.0944J/g^oC$

Explanation :

For part A :

Heat released by the metal = Heat absorbed by the calorimeter + Heat absorbed by the water

$q=[q_1+q_2]$

$q=[c_1\times \Delta T+m_2\times c_2\times \Delta T]$

where,

q = heat released by the metal

$q_1$ = heat absorbed by the calorimeter

$q_2$ = heat absorbed by the water

$c_1$ = specific heat of calorimeter = $51.5J/^oC$

$c_2$ = specific heat of water = $4.184J/g^oC$

$m_2$ = mass of water = 50.0 g

$\Delta T$ = change in temperature = $(T_{final}-T_{initial})=23.2-22.0=1.2^oC$

Now put all the given values in the above formula, we get:

$q=[(51.5J/^oC\times 1.2^oC)+(50.0g\times 4.184J/g^oC\times 1.2^oC)]$

$q=312.48J$

Thus, the heat released by the metal is -312.48 J

For part B :

$q=m\times c\times \Delta T$

q = heat released by the metal = -312.48 J

m = mass of metal = 43.1 g

c = specific heat of metal = ?

$\Delta T$ = change in temperature = $(T_{final}-T_{initial})=23.2-100=76.8^oC$

Now put all the given values in the above formula, we get:

$-312.48J=43.1g\times c\times 76.8^oC$

$c=0.0944J/g^oC$

Thus, the specific heat of the metal is $0.0944J/g^oC$

8 0

3 years ago

A brown coating appears on the outside of the nail.what do you think this is?

Talja [164]

Answer:

Rusting

I guess

Explanation:

Cause in iron if a brown coating appears it is called rusting

8 0

2 years ago

Most of the costs associated with using renewable resources are due to

saveliy_v [14]

Answer:

a. overuse of resources is the correct answer.

Explanation:

Renewable resources are available and they are abundant but overuse of these renewable resources will have a negative effect on the surroundings and humans.

Overuse of renewable resources will leads to the depletion of these renewable sources in the future and will also make the ecosystem unbalance.

Renewable resources are solar energy, geothermal energy, biomass energy, wind energy, hydro energy.

Thus renewable resources are threatened due to overuse and it must be carefully used.

6 0

3 years ago

Suppose that a catalyst lowers the activation barrier of a reaction from 125kJ/mol to 55kJ/mol125⁢kJ/mol to 55kJ/mol. By what fa

sineoko [7]

Answer:

The factor of increasing reaction rate is 1,85x10¹².

Explanation:

Using arrhenius formula:

$k = A e^\frac{-E_{a}}{RT}$

Where k is rate constant; A is frecuency factor; Eₐ is activation energy; R is gas constant (0,008134 kJ/molK); T is temperature 25°C = 298,15K

Thus, replacing for an activation energy of 125 kJ/mol assuming A as 1:

k = 1,25x10⁻²²

When activation energy is 55kJ/mol:

k = 2,31x10⁻¹⁰

Thus, the factor of increasing reaction rate is:

2,31x10⁻¹⁰/1,25x10⁻²² = 1,85x10¹²

I hope it helps!

8 0

3 years ago