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Annette [7]
3 years ago
11

How many atoms are in a 0.50 g sample of helium

Chemistry
1 answer:
Mrac [35]3 years ago
3 0
0.5 G is your answer for this question
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I need an answer now please asap and you will me marked brainiest please it's missing I need it now.
valentina_108 [34]

Answer:

C. NaHCO3 → Na2CO3 + H2O + CO2

Explanation:

» For a balanced equation, the number of atoms of reactants and products must be equal.

» In equation C, the reactant side has one sodium atom while ptoduct side has 2 sodium atoms.

» The balanced equations mus be;

{ \rm{ 2NaHCO _{3(aq)} → Na _{2}CO _{3(s)}+ H _{2} O _{(l)} + }CO _{2(g)} }

7 0
2 years ago
Read 2 more answers
A sample of an ionic compound NaA, where A- is the anion of a
vitfil [10]

Answer:

a) Kb = 10^-9

b) pH = 3.02

Explanation:

a) pH 5.0 titration with a 100 mL sample containing 500 mL of 0.10 M HCl, or 0.05 moles of HCl. Therefore we have the following:

[NaA] and [A-] = 0.05/0.6 = 0.083 M

Kb = Kw/Ka = 10^-14/[H+] = 10^-14/10^-5 = 10^-9

b) For the stoichiometric point in the titration, 0.100 moles of NaA have to be found in a 1.1L solution, and this is equal to:

[A-] = [H+] = (0.1 L)*(1 M)/1.1 L = 0.091 M

pKb = 10^-9

Ka = 10^-5

HA = H+ + A-

Ka = 10^-5 = ([H+]*[A-])/[HA] = [H+]^2/(0.091 - [H+])

[H+]^2 + 10^5 * [H+] - 10^-5 * 0.091 = 0

Clearing [H+]:

[H+] = 0.00095 M

pH = -log([H+]) = -log(0.00095) = 3.02

6 0
3 years ago
Which of the following conditions will result in a reaction that is spontaneous only at high temperatures?
Korolek [52]
You have to use the equation ΔG=ΔH-TΔS.
With that equation you know that a reaction with a positive change in enthalpy and positive change in entropy will only be spontaneous at high temperatures since ΔG needs to be negative for a reaction to be spontaneous.

I hopet this helps.  Let me know if anything is unclear.
6 0
3 years ago
What is the order of epoch eon era and period from big to small?
Neko [114]

smallest to largest: epoch, period, era, eon

4 0
3 years ago
2.61 kilograms of water in a container have a pressure of 200 kPa and temperature of 200°C . What is the volume of this containe
Arisa [49]

<u>Answer:</u> The volume of the container is 2.8497m^3

<u>Explanation:</u>

To calculate the volume of water, we use the equation given by ideal gas, which is:

PV=nRT

or,

PV=\frac{m}{M}RT

where,

P = pressure of container = 200 kPa

V = volume of container = ? L

m = Given mass of water = 2.61 kg = 2610 g   (Conversion factor: 1kg = 1000 g)

M = Molar mass of water = 18 g/mol

R = Gas constant = 8.31\text{L kPa }mol^{-1}K^{-1}

T = temperature of container = 200^oC=[200+273]K=473K

Putting values in above equation, we get:

200kPa\times V=\frac{2610g}{18g/mol}\times 8.31\text{L kPa }\times 473K\\\\V=2849.7L

Converting this into cubic meter, we use the conversion factor:

1m^3=1000L

So, \Rightarrow \frac{1m^3}{1000L}\times 2849.7L

\Rightarrow 2.8497m^3

Hence, the volume of the container is 2.8497m^3

6 0
3 years ago
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