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deff fn [24]
2 years ago
8

Please help Please Help

Chemistry
1 answer:
Sveta_85 [38]2 years ago
8 0

Answer:

1) false

2) true

3) true

4) false

5) false. I think

6) false

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If nitrogen (N) has 2 naturally occurring isotopes, nitrogen-14 (78.3%) and nitrogen-16 (21.7%), what is its average r.a.m.?
leva [86]

Answer:

14.434 r.a.m.

Explanation:

  • The atomic mass of an element is a weighted average of its isotopes in which the sum of the abundance of each isotope is equal to 1 or 100%.

∵ The atomic mass of N = ∑(atomic mass of each isotope)(its abundance)

∴ The atomic mass of N = (atomic mass of N-14)(abundance of N-14) + (atomic mass of N-16)(abundance of N-16)

atomic mass of N-14 = 14.0 r.a.m, abundance of N-14 = percent of N-14/100 = 78.3/100 = 0.783.

atomic mass of N-16 = 16.0 r.a.m, abundance of N-16 = percent of N-16/100 = 21.7/100 = 0.217.

∴ The atomic mass of N = (atomic mass of N-14)(abundance of N-14) + (atomic mass of N-16)(abundance of N-16) = (14.0 r.a.m)(0.783) + (16.0 r.a.m)(0.217) = 14.434 r.a.m.

5 0
2 years ago
Which rock type is an example of igneous glass?
irinina [24]

Answer:

obsidian

Explanation:

because it is an igneous rock which is smooth

5 0
2 years ago
What is the number of moles of solute in a 0.3 molal solution containing 0.10 kg of solvent? Don't forget the unit.
timurjin [86]
Molality is one way of expressing concentration for solutions. It has units of moles of solute per kg of solvent. From the given values, we easily calculate for the moles of solute by multiplying the mass of solvent to the molality. We do as follows:

moles solute = 0.3 (10) = 3 mol solute


5 0
3 years ago
Read 2 more answers
The addition of 250.0 J to 30.0 g of copper initially at 22.0°C will change its temperature to what final value? (Specific heat
WINSTONCH [101]

Answer:

Final temperature = 43.53^{\circ} C

Explanation:

Given that,

Heat added, Q = 250 J

Mass, m = 30 g

Initial temperature, T₁ = 22°C

The Specific heat of Cu= 0.387 J/g °C

We know that, heat added due to the change in temperature is given by :

Q=mc\Delta T\\\\Q=mc(T_2-T_1)\\\\\dfrac{Q}{mc}=(T_2-T_1)\\\\T_2=\dfrac{Q}{mc}+T_1

Put all the values,

T_2=\dfrac{250}{30\times 0.387}+22\\\\=43.53^{\circ} C

So, the final temperature is equal to 43.53^{\circ} C.

8 0
3 years ago
CHEM PLZ HELP
marusya05 [52]

Answer:

Increase in CO2 (g) over time.

No NaHCO3 (s) will be left after a time

Explanation:

The reaction, shown below;

2NaHCO3(s) → Na2CO3(s)+CO2(g)+H2O(ℓ) is a decomposition reaction. A decomposition reaction is a kind of chemical reaction in which a given chemical specie breaks up to give other chemical species. Decomposition may be induced by heat or light.

Usually, there is only one reactant in a decomposition reaction; the specie that disintegrates into the products. This reactant usually decreases in concentration steadily because it is converted into products. This is why the mass of NaHCO3(s) in the system continues to decrease steadily until it finally falls to zero.

Conversely, the concentration (for aqueous) or volume (for gases) or mass (for solid) products of the reaction increases steadily as the reaction progresses. This explains why the volume of CO2 in the system will steadily increase over time.

7 0
3 years ago
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