CNC NaCl HCL are all classified as

Minerals are very useful to us. Which of the following is a false statement? Question options: Pyrite is an ore of gold and is u

lilavasa [31]

Answer:

The false statement is :

Pyrite is an ore of gold and is used in jewelry making.
Cobalt is not used in medicine.

Explanation:

Pyrite is an ore of iron sulfide found on the Earth and in coal, limestone and in many deposits of metallic ores. Due to its luster and pale yellowish color it appears as gold due to which it is also termed as Fool's gold.

It is used in firearms , in production of sulfur dioxide gas, etc.

Cobalt is used as medicine to treat cancer patient. Co-60 is used in treatment of cancer in which gamma rays produced by Co-60 are used to kill tumor cells in a cancer patient.

Where as talc is used in industries like : paper making, food, paints, plastics etc. Quartz is primary material used to prepare glass and cobalt is used as

4 0

3 years ago

write a balanced chemical equation for each single replacement reaction that takes place in aqueous solution. write no reaction

Illusion [34]

The question is incomplete, here is the complete question:

Write a balanced chemical equation for each single replacement reaction that takes place in aqueous solution. write no reaction if a reaction does not occur

1.) Zn + PbCl₂

2.) Cu + Fe(NO₃)₂

Answer:

For 1: The reaction does occur.

For 2: The reaction does not occur.

Explanation:

Single displacement reaction is defined as the reaction in which more reactive element displaces a less reactive element.

The reactivity of metal is determined by a series known as reactivity series. The metals lying above in the series are more reactive than the metals which lie below in the series.

$A+BC\rightarrow AC+B$

For the given options:

For 1:

Zinc is more reactive than lead as it lies above in the series. So, it will displace lead from its chemical equation.

The chemical equation for the reaction of zinc and lead chloride follows:

$Zn+PbCl_2\rightarrow ZnCl_2+Pb$

For 2:

Copper is less reactive than iron as it lies below in the series. So, it will not displace iron from its chemical equation.

The chemical equation for the reaction of copper and iron (II) nitrate follows:

$Cu+Fe(NO_3)_2\rightarrow \text{No reaction}$

3 0

3 years ago

An unknown piece of metal weighing 95.0 g is heated to 98.0°C. It is dropped into 250.0 g of water at 23.0°C. When equilibrium i

lutik1710 [3]

Answer:

$C_{metal}=126.6\frac{J}{g\°C}$

Explanation:

Hello!

In this case, when two substances at different temperature are put in contact and an equilibrium temperature is attained, we can evidence that the heat lost by the hot substance (metal) is gained by the cold substance (water) and we can write:

$Q_{metal}=-Q_{water}$

Which can be also written as:

$m_{metal}C_{metal}(T_{EQ}-T_{metal})=-m_{water}C_{water}(T_{EQ}-T_{water})$

Thus, since we need the specific heat of the metal, we solve for it as shown below:

$C_{metal}=\frac{m_{water}C_{water}(T_{EQ}-T_{water})}{-m_{metal}(T_{EQ}-T_{metal})} \\\\C_{metal}=\frac{250.0g*4.184\frac{J}{g\°C}(29.0\°C-98.0\°C)}{95.0g(29.0\°C-23.0\°C)} \\\\C_{metal}=126.6\frac{J}{g\°C}$

Best regards.

7 0

2 years ago

How is the energy of the universe conserved during the combustion of gasoline in a car engine?

Marianna [84]

In a car driven by a gasoline combustion engine, heat energy is quickly converted into kinetic energy which results in the motion of the car.

According to the law of the conservation of energy, energy cannot be destroyed or created. It is can only be transformed from one form to another.

6 0

2 years ago

Read 2 more answers

The molar heat capacity of ethane is represented in the temperature range 298 K to 400 K by the empirical expression Cp,m in J K

BabaBlast [244]

Answer:

-88.66 kJ/mol

Explanation:

The expressions of heat capacity (Cp,m) for C(s) and for H₂(g) are:

C(s): Cp,m/(J K-1 mol-1) = 16.86 + (4.77T/10³) - (8.54x10⁵/T²)

H₂(g): Cp,m/(J K-1 mol-1) = 27.28 + (3.26T/10³) + (0.50x10⁵/T²)

Cp = A + BT + CT⁻²

For the Kirchoff's Law:

ΔHf = ΔH°f + $\int\limits^{T2}_{T1} {DCp(T)} \, dT$

Where ΔH°f is the enthalpy at 298 K, T1 is 298 K, T2 is the temperature given (373 K), and DCp is the variation of Cp (products less reactants). ΔH°f for ethene is -84.68 kJ/mol and the reaction is:

2C(s) + 3H₂(g) → C₂H₆

So, DCp:

dA = A(C₂H₆) - [2xA(C) + 3xA(H₂)] = 14.73 - [2x16.86 + 3x27.28] = -100.83

dB = B(C₂H₆) - [2xB(C) + 3xB(H₂)] = 0.1272 - [2x4.77x10⁻³ + 3x3.26x10⁻³] = 0.10788

dC = C(C₂H₆) - [2xC(C) + 3xC(H₂)] = 0 - (2x(-8.54x10⁵) + 3x0.50x10⁵) = 15.58x10⁵

dCp = -100.83 + 0.10788T + 15.58x10⁵T⁻²

$\int\limits^{373}_{298} {-100.83 + 0.10788T + 15.58x10^5T^{-2}} \, dT$ = -3796.48 J/mol = -3.80 kJ/mol (solved by a graphic calculator)

ΔHf = -84.68 - 3.80

ΔHf = -88.66 kJ/mol

7 0

2 years ago