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3 years ago

Please help!! Having trouble with this

Chemistry

1 answer:

Gnoma [55]3 years ago

7 0

For #4 first find the molar mass(M) of copper then use that and the mass (m) n=m/M to find moles(n) using moles and the volumes find the concentration using c=n/V

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How many moles of water are formed when 22 mol of methane combusts?

icang [17]

Methane is a hydrocarbon which when burns in air (combustion) produces carbon dioxide and water. The equation for the reaction;
CH4 +2O2 = CO2 +2H2O
When one mole of methane combusts 2 moles of water are formed
Therefore; when 22 moles of methane combusts 44 moles of water are formed (22 ×2)

7 0

3 years ago

A buffer solution is made that is 0.347 M in H2C2O4 and 0.347 M KHC2O4.

irga5000 [103]

Answer:

1. pH = 1.23.

2. $H_2C_2O_4(aq) +OH^-(aq)\rightarrow HC_2O_4^-(aq)+H_2O(l)$

Explanation:

Hello!

1. In this case, for the ionization of H2C2O4, we can write:

$H_2C_2O_4\rightleftharpoons HC_2O_4^-+H^+$

It means, that if it is forming a buffer solution with its conjugate base in the form of KHC2O4, we can compute the pH based on the Henderson-Hasselbach equation:

$pH=pKa+log(\frac{[base]}{[acid]} )$

Whereas the pKa is:

$pKa=-log(Ka)=-log(5.90x10^{-2})=1.23$

The concentration of the base is 0.347 M and the concentration of the acid is 0.347 M as well, as seen on the statement; thus, the pH is:

$pH=1.23+log(\frac{0.347M}{0.347M} )\\\\pH=1.23+0\\\\pH=1.23$

2. Now, since the addition of KOH directly consumes 0.070 moles of acid, we can compute the remaining moles as follows:

$n_{acid}=0.347mol/L*1.00L=0.347mol\\\\n_{acid}^{remaining}=0.347mol-0.070mol=0.277mol$

It means that the acid remains in excess yet more base is yielded due to the effect of the OH ions provided by the KOH; therefore, the undergone chemical reaction is:

$H_2C_2O_4(aq) +OH^-(aq)\rightarrow HC_2O_4^-(aq)+H_2O(l)$

Which is also shown in net ionic notation.

Best regards!

4 0

3 years ago

The two boron atoms listed in the table are isotopes of the boron. The two carbon atoms and the two oxygen atoms are also called

Ivan

Answer:

A type of an atom which has a different number of neutrons but the same atomic number, therefore making it the same element. This atom would still have the same properties as well. (Ex: Vanadium-51 is an isotope of Vanadium that has 51 neutrons but still has 23 protons, as its atomic number is 23.)

3 0

2 years ago

describe the relationship between the energy of an electron, and its probable distance away from the nucleus of an atom?

mel-nik [20]

Answer: The energy of an electron depends on its location with respect to the nucleus of an atom. The higher the energy of an electron in an atom, the farther is its most probable location from the nucleus.

8 0

3 years ago

25.0 mL of nitrous acid (HNO2) is titrated with a 1.235 M solution of KOH. The equivalence point (stoichiometric point) is obser

tatuchka [14]

Answer:

0.456 M

Explanation:

Step 1: Write the balanced neutralization equation

HNO₂ + KOH ⇒ KNO₂ + H₂O

Step 2: Calculate the reacting moles of KOH

9.26 mL of 1.235 M KOH react.

0.00926 L × 1.235 mol/L = 0.0114 mol

Step 3: Calculate the reacting moles of HNO₂

The molar ratio of HNO₂ to KOH is 1:1. The reacting moles of HNO₂ are 1/1 × 0.0114 mol = 0.0114 mol.

Step 4: Calculate the initial concentration of HNO₂

0.0114 moles of HNO₂ are in 25.0 mL of solution.

[HNO₂] = 0.0114 mol / 0.0250 L = 0.456 M

3 0

3 years ago