Chemistry Answers

"The smallest bone in the human body, which is in the ear, has a mass of 0.0030 g. what is the mass of this bone in pounds?"

The following industrial processes produce ethanol.

Hydration of ethene: C2H4(g) + H2O(g) =C2H5OH(l)

Fermentation of glucose: C6H12O6(aq) = 2C2H5OH(aq) + 2CO2(g)

(a) What is the atom economy by mass of the fermentation process?

A) 25.6%

B) 46.0%

C) 51.1%

D) 92.0%

A gas has a volume of 3.00 L and a pressure of 75.4 kPa. when the volume expands to 4.00 L and the pressure drops to 72.7 kPa, the gas temperature is 0C. what was the initial temperature of the gas?

Observation for silver nitrate sol is mixed with HCl/NaCl

Hello, will you kindly help me

1) Matter and energy are

a) similar to work and distance.

b) interconvertible

c) not related to each other

d) similar to mass and weight

which of the following has the greater mass ?

a) 1.25 kg of lead b) 1.25 kg of aluminum c) 1.25 kg of cotton d) 1.25 kg feathers e) none of the above

A vessel of volume 5 liters was filled with 2 moles of hydrogen gas (a), then a further 1 mole of chlorine gas (b), and then the mixture was sparked leading to the formation of 1 mole of HCl (g) (c). What are the partial pressure of the components and the total pressure of the system at the final stage. The temperature being 25oC throughout.

6. Suppose that you are travelling in the Space Shuttle Endeavor on a journey to Mars. The atmosphere (of the vehicle) consists of 20% oxygen and 80% helium by volume. It was noticed before take off from the Kennedy Space Center that there is a small leakage which if unchecked, would lead to a continual loss of gas at a rate of 0.05 atm/day through effusion. If the temperature in the space shuttle is maintained at 22oC and the volume of the vehicle is 15,000 liters. Calculate the amounts of helium and oxygen in grams that must be stored on a 5-day journey to allow for the leakage.

A reversible reaction of methanol (M) dehydrogenation to formaldehyde (F) and hydrogen (H):

CH₃OH ⇄ CH₂O + H₂

is characterized by an equilibrium constant K_C = 10 at a temperature t = 670°C. Given the following values of standard molar entropies:

S^⦵_M = 239,9 J/(mol·K)

S^⦵_F = 218,9 J/(mol·K)

S^⦵_H = 130,7 J/(mol·K)

Calculate the value of standard enthalpy of this reaction (∆H^⦵_R)

Universal gas constant R = 8,314 J/(mol·K)

1.    A sample of material weighing m = 3.400 g was incinerated inside a bomb calorimeter. The calorimeter was charged with m_W = 1500 g of water. The initial temperature of the calorimeter was t₀ = 24.223°C. After the incineration the temperature rose to t₁ = 29.654°C.

Calculate the heat of combustion of 1 kg of tested material.

Heat capacity of the calorimeter: c_P,(c) = 3.3 kJ/K

Specific heat of water: C_P,(W) = 4.18 kJ/(kg·K)

1.     A first-order reaction reaches a conversion equal to X₁ = 0.75 in τ₁ = 10 minutes. Calculate the time τ₂ required to reach conversion X₂ = 0.9