3. Perform each calculation to the correct number of significant figures.

ruslelena [56]

Answer:

H₂O + CO₂ → H₂CO₃

Option D is correct.

Law of conservation of mass:

According to this law, mass can neither be created nor destroyed in a chemical equation.

This law was given by French chemist Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.

Now we will apply this law to given chemical equations:

A) H₂ + O₂ → H₂O

There are two H and two O atoms present on left side while on right side only one O and two H atoms are present so mass in not conserved. This option is incorrect.

B) Mg + HCl → H₂ + MgCl₂

In this equation one Mg, one H and one Cl atoms are present on left side of equation while on right side two H, one Mg and two chlorine atoms are present. This equation also not follow the law of conservation of mass.

C) KClO₃ → KCl + O₂

There are one K, one Cl and three O atoms are present on left side of equation while on right side one K one Cl and two oxygen atoms are present. This equation also not following the law of conservation of mass.

D) H₂O + CO₂ → H₂CO₃

There are two hydrogen, one carbon and three oxygen atoms are present on both side of equation thus, mass remain conserved. This option is correct.

5 0

4 years ago

A galvanic cell at a temperature of 25.0°C is powered by the following redox reaction:

Vlada [557]

Answer: The cell voltage of the given chemical reaction is 2.74 V

Explanation:

For the given chemical reaction:

$Sn^{2+}(aq.)+Ba(s)\rightarrow Ba^{2+}(aq.)+Sn(s)$

Here, gold is getting reduced because it is gaining electrons and nickel is getting oxidized because it is loosing electrons.

Oxidation half reaction: $Ba(s)\rightarrow Ba^{2+}(aq.)+2e^-;E^o_{Ba^{2+}/Ba}=-2.90V$

Reduction half reaction: $Sn^{2+}(aq.)+2e^-\rightarrow Sn(s);E^o_{Sn^{2+}/Sn}=-0.14V$

Substance getting oxidized always act as anode and the one getting reduced always act as cathode.

To calculate the $E^o_{cell}$ of the reaction, we use the equation:

$E^o_{cell}=E^o_{cathode}-E^o_{anode}$

$E^o_{cell}=-0.14-(-2.90)=2.76V$

To calculate the EMF of the cell, we use the Nernst equation, which is:

$E_{cell}=E^o_{cell}-\frac{0.059}{n}\log \frac{[Sn^{2+}]}{[Ba^{2+}]}$

where,

$E_{cell}$ = electrode potential of the cell = ?V

$E^o_{cell}$ = standard electrode potential of the cell = +2.76 V

n = number of electrons exchanged = 2

$[Ba^{2+}]=5.15M$

$[Sn^{2+}]=1.59M$

Putting values in above equation, we get:

$E_{cell}=2.76-\frac{0.059}{2}\times \log(\frac{1.59}{5.15})\\\\E_{cell}=2.74V$

Hence, the cell voltage of the given chemical reaction is 2.74 V

8 0

4 years ago

Convert 10 grams of hydrogen gas to moles

polet [3.4K]

So the molar mass of a Hydrogen molecule is 2. If you have 10 grams of Hydrogen molecules, you have 5 moles of Hydrogen molecules (10 moles of Hydrogen atoms). Avogadro's number is 6.0225x10^23. This means that one mole of a substance has that many particles.

7 0

3 years ago

Rank these elements according to first ionization energy. Sb, As, P, N

kogti [31]

Highest ionization energy to lowest: N, P, As, Sb.

5 0

4 years ago

Read 2 more answers

¿Quién estableció el concepto moderno de elemento?

Zina [86]

Answer:

Robert Boyle

Explanation:

En muchos textos se suele considerar a Robert Boyle como el científico que introdujo en la Química un concepto de elemento diferente al empleado por los aristotélicos o por los alquimistas y que sirvió de antecedente al que formulara Lavoisier en 1789.

7 0

3 years ago