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Reika [66]
2 years ago
9

8.45 cm - 3.55 cm = ?

Chemistry
2 answers:
lyudmila [28]2 years ago
6 0

Answer:

4.9cm or 4.90cm

Explanation:

Use column method and align the numbers. Make sure you add the decimal point before you write the answer, otherwise the value would be wrong.

mafiozo [28]2 years ago
5 0

Answer:

4.90

Explanation:

8.45.

-3.55

minus those two and you'll get the sum!

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At 73.0 ∘c , what is the maximum value of the reaction quotient, q, needed to produce a non-negative e value for the reaction so
damaskus [11]
Here we will use the general formula of Nernst equation:

Ecell = E°Cell - [(RT/nF)] *㏑Q

when E cell is cell potential at non - standard state conditions

E°Cell is standard state cell potential = - 0.87 V

and R is a constant = 8.314 J/mol K

and T is the temperature in Kelvin = 73 + 273 = 346 K

and F is Faraday's constant = 96485 C/mole

and n is the number of moles of electron transferred in the reaction=2  

and Q is the reaction quotient for the reaction 
SO42-2(aq) + 4H+(aq) +2Br-(aq) ↔  Br2(aq) + SO2(g) +2H2O(l)

so by substitution :

0 = -0.87 - [(8.314*346K)/(2* 96485)*㏑Q      → solve for Q 


∴ Q = 4.5 x 10^-26 
6 0
2 years ago
The gas described in parts a and b has a mass of 1.66 g. the sample is most likely which monatomic gas?
nordsb [41]
Mass of the gas m = 1.66 
The calculated temperature T = 273 + 20 = 293
 We have to calculate molar mass to determine the gas
 Molar Mass = mRT / PV
 M = (1.66 x 8.314 x 293) / (101.3 x 1000 x 0.001)
 M = 4043.76 / 101.3 = 39.92 g/mol
 So this gas has to be Argon Ar based on the molar mass.

7 0
2 years ago
Read 2 more answers
One of the buffers that contribute to pH stability in human blood is carbonic acid (H2CO3). Carbonic acid is a weak acid that, w
bonufazy [111]

Answer: the HCO3- to act as a base and remove excess H by the formation of H2CO3

Explanation:

H2CO3 in an aqueous solution is a buffer. This means the reaction is the following:

H2CO3 ------ HCO3- + H+

Then, the HCO3- that was formed acts as a base (absorbing a proton) like this

HCO3- + H+ ------- H2CO3

If there was an increase in H+, there would be an increase in the second reaction in an effort to neutralize that acid, thus making the H2CO3 more concentrated

7 0
2 years ago
At 1.01 bar, how many moles of CO2 are released by raising the temperature of 1 litre of water from 20∘C to 25∘C
Tatiana [17]

Answer: 0.0007 moles of CO_2 is released when temperature is raised.

Explanation:

To calculate the number of moles, we use the ideal gas equation, which is:

PV=nRT

where,

P = pressure of the gas = 1.01 bar

V = Volume of the gas = 1L

R = Gas constant = 0.08314\text{ L bar }mol^{-1}K^{-1}

  • Number of moles when T = 20° C

Temperature of the gas = 20° C = (273 + 20)K = 293K

Putting values in above equation, we get:

1.01bar\times 1L=n_1\times 0.0814\text{ L bar }mol^{-1}K^{-1}\times 293K\\n_1=0.04146moles

  • Number of moles when T = 25° C

Temperature of the gas = 25° C = (273 + 25)K = 298K

Putting values in above equation, we get:

1.01bar\times 1L=n_2\times 0.0814\text{ L bar }mol^{-1}K^{-1}\times 298K\\n_2=0.04076moles

  • Number of moles released = n_1-n_2=0.04146-0.04076=0.0007moles

Hence,  0.0007 moles of CO_2 is released when temperature is raised from 20° C to 25° C

5 0
2 years ago
Using the equations 2 Sr(s) + O₂ (g) → 2 SrO (s) ∆H° = -1184 kJ/mol SrO (s) + CO₂ (g) → SrCO₃ (s) ∆H° = -234 kJ/mol CO₂ (g) → C(
kkurt [141]

<u>Answer:</u> The \Delta H^o_{rxn} for the reaction is 72 kJ.

<u>Explanation:</u>

Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.

According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.

The given chemical reaction follows:

2SrCO_3(s)\rightarrow 2Sr(s)+2C(s)+3O_2(g)      \Delta H^o_{rxn}=?

The intermediate balanced chemical reaction are:

(1) 2Sr(s)+O_2(g)\rightarrow 2SrO(s)    \Delta H_1=-1184kJ

(2) SrO(s)+CO_2(g)\rightarrow SrCO_3(s)     \Delta H_2=-234kJ      ( × 2)

(3) CO_2(g)\rightarrow C(s)+O_2(g)     \Delta H_3=394kJ    ( × 2)

The expression for enthalpy of the reaction follows:

\Delta H^o_{rxn}=[1\times (\Delta H_1)]+[2\times (-\Delta H_2)]+[2\times (\Delta H_3)]

Putting values in above equation, we get:

\Delta H^o_{rxn}=[(1\times (-1184))+(2\times -(-234))+(2\times (394))]=72kJ

Hence, the \Delta H^o_{rxn} for the reaction is 72 kJ.

4 0
2 years ago
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