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3 years ago

True or false?? All atoms of the same element have the same atomic mass

Chemistry

2 answers:

AnnyKZ [126]3 years ago

8 0

Answer:

False

Explanation:

rewona [7]3 years ago

8 0

Answer:

Atoms with the same number of protons but different number of neutrons are called isotopes. Interpretation: If the statement“All isotopes of an element have the same number of electrons”.

Explanation:

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A 1.28-kg sample of water at 10.0 °C is in a calorimeter. You drop a piece of steel with a mass of 0.385 kg at 215 °C into it. A

Kryger [21]

Answer:

$T_{2}=16,97^{\circ}C$

Explanation:

The specific heats of water and steel are

$Cp_{w}=4.186 \frac{KJ}{Kg^{\circ}C}$

$Cp_{s}=0.49 \frac{KJ}{Kg^{\circ}C}$

Assuming that the water and steel are into an adiabatic calorimeter (there's no heat transferred to the enviroment), the temperature of both is identical when the system gets to the equilibrium $T_{2}_{w}= T_{2}_{s}$

An energy balance can be written as

$m_{w}\times Cp_{w}\times (T_{2}- T_{1})_{w}= -m_{s}\times Cp_{s}\times (T_{2}- T_{1})_{s}$

Replacing

$1.28Kg\times 4.186\frac{KJ}{Kg^{\circ}C}\times (T_{2}-10^{\circ}C)= -0.385Kg\times 0.49 \frac{KJ}{Kg^{\circ}C} \times (T_{2}-215^{\circ}C)$

Then, the temperature $T_{2}=16,97^{\circ}C$

8 0

2 years ago

Which statement BEST describes why licensed health care workers are held to a higher standard?

strojnjashka [21]

Answer:

They agree to ethical standards when they are licensed.

Explanation:

4 0

3 years ago

How is the mass number of an isotope expressed in the name of an atom?

Ksenya-84 [330]

The mass number of an isotope can be expressed by simply writing the name of the element or symbol followed by a hyphen and the mass number.

Example:
Carbon-13, Carbon-14
Oxygen-17
Uranium-235

6 0

3 years ago

Ammonia will decompose into nitrogen and hydrogen at high temperature. An industrial chemist studying this reaction fills a 500.

patriot [66]

Explanation:

Chemical reaction equation for the give decomposition of $NH_{3}$ is as follows:.

$2NH_{3}(g) \rightleftharpoons N_{2}(g) + 3H_{2}(g)$

And, initially only $NH_{3}$ is present.

The given data is as follows.

$P_{NH_{3}}$ = 2.3 atm at equilibrium

$P_{H_{2}} = 3 \times P_{N_{2}}$ = 0.69 atm

Therefore,

$P_{N_{2}} = \frac{0.69 atm}{3}$

= 0.23 aatm

So, $P_{NH_{3}}$ = 2.3 - 2(0.23)

= 1.84 atm

Now, expression for $K_{p}$ will be as follows.

$K_{p} = \frac{(P_{N_{2}})(P^{3}_{H_{2}})}{(P^{2}_{NH_{3}})}$

$K_{p} = \frac{(0.23) \times (0.69)^{3}}{(1.84)^{2}}$

= $\frac{0.23 \times 0.33}{3.39}$

= 0.0224

or, $K_{p} = 2.2 \times 10^{-2}$

Thus, we can conclude that the pressure equilibrium constant for the decomposition of ammonia at the final temperature of the mixture is $2.2 \times 10^{-2}$ .

6 0

3 years ago

Enter the simplified version of the expression below. (4.7x - 3.25) + (-5.5 - 1.25x)

Amiraneli [1.4K]

3.45x-8.75 is the simplified version:)

4 0

3 years ago