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alekssr [168]
3 years ago
9

The mass numbers for two isotopes are unequal because they have different numbers of

Chemistry
2 answers:
Savatey [412]3 years ago
8 0

<u>Answer:</u> It is so because they have different number of neutrons.

<u>Explanation:</u>

Isotopes are defined as the chemical species which have same number of protons but differ in the number of neutrons.

They have same atomic number but different atomic mass.

<u>For Example:</u>  _6^{12}\textrm{C},_6^{13}\textrm{C}\text{ and }_6^{14}\textrm{C} are the three isotopes of carbon.

The number of protons in all the three isotopes is same which is 6 and the number of neutrons in the three isotopes are 6, 7 and 8 respectively.

Hence, it is so because they have different number of neutrons.

SSSSS [86.1K]3 years ago
5 0
The mass numbers for two isotopes are unequal because they have different numbers of NEUTRONS.

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Given the standard enthalpy changes for the following two reactions:
lawyer [7]

Answer:

ΔH° = -186.2 kJ

Explanation:

Hello,

This case in which the Hess method is applied to compute the required chemical reaction. Thus, we should arrange the given first two reactions as:

(1) it is changed as:

SnCl2(s) --> Sn(s) + Cl2(g)...... ΔH° = 325.1 kJ

That is why the enthalpy of reaction sign is inverted.

(2) remains the same:

Sn(s) + 2Cl2(g) --> SnCl4(l)......ΔH° = -511.3 kJ

Therefore, by adding them, we obtain the requested chemical reaction:

(3) SnCl2(s) + Cl2(g) --> SnCl4(l)

For which the enthalpy change is:

ΔH° = 325.1 kJ - 511.3 kJ

ΔH° = -186.2 kJ

Best regards.

7 0
3 years ago
Read 2 more answers
A. How the molecules in a solid, liquid and gas compare to each other.
andre [41]
A. The molecules of solids are close together and compact, liquids are spread out but not too far apart, and gas molecules are really far apart.

B. Increase in temperature causes pressure to go up. Decrease in temperature cause pressure to go down
8 0
3 years ago
An organic fertiliser in which plants are ploughed back into the soil​
Evgen [1.6K]

Answer:

It was called MANURE

Explanation:

Its a type of fertilizer which plant are ploughed back into the soil.

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7 0
3 years ago
An iron block of mass 18 kg is heated from 285 K to 318 K. If 267.3 kJ is required, what is the specific heat of iron? A. 450.00
valkas [14]

Answer:

  • <u>Option A. 450.00</u>

Explanation:

<u>1) Data:</u>

a) m = 18 kg

b) T₁ = 285 K

c) T₂ = 318 K

d) Q = 267.3 kJ

e) S = ?

<u>2) Principles and equations</u>

The specific heat of a substance is the amount of heat energy absorbed to increase the temperature of certain amount (gram, kg, or moles, depending on the definition or units) of the substance in 1 ° C or 1 K.

The mathematical relation between the specific heat and the heat energy absorbed is:

  • Q = m × S × ΔT

Where,

  • Q is the heat absorbed,
  • S is the specific heat, and
  • ΔT is the temperature increase (T₂ - T₁)

<u>3) Solution:</u>

<u>a) Substitute the data into the equation:</u>

  • 267.3 kJ = 18 kg × S × (318 K - 285 K)

<u>b) Solve for S and compute:</u>

  • S = 267.3 kJ / (18 kg × 33 K) = 0.45 kJ / (Kg . K)

The options have not units, but I notice that the first answer is 1,000 times the answer I obtained, so I will make a conversion of units.

<u>c) Convert to J /( kg . k):</u>

  • 0.45 kJ / (Kg . K) × 1,000 J / kJ = 450 J / (kg . K)

Now we can see that the option A is is the answer, assuming the units.

6 0
4 years ago
3.75 g of an unknown gas at 59 °C and 1.00 atm is stored in a 1.35-L flask. What is the molar mass of the gas?
MAXImum [283]
You need to find moles of the gas, so you would use the ideal gas law:
PV=nRT
Pressure
Volume
n=moles
R= gas constant
Tenperature in Kelvin
n= PV/RT
(1.00atm)(1.35L)/(.08206)(332K) = 0.050mol
Molar mass is grams per mole, so
(3.75g/.050mol) = 75g/mol
4 0
3 years ago
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