All categories

2 years ago

First law of Thermodynamics

Chemistry

1 answer:

guapka [62]2 years ago

7 0

Answer:

Thermal energy is taken from heat sink in higher temperature. A thermal power machine does mechanical energy using part of the heat.

Part of heat taken are given in cold reservoir in lower temperature

Explanation:

You might be interested in

How does the body react when the outside temperature gets too hot

mr_godi [17]

When temperatures rise, the body reacts by increasing blood flow to the skin's surface, taking the heat from within the body to the surface. This means sweat. ... If, as in the UK, our skin temperature is warmer than the external temperature we are also able to lose heat to the environment, termed 'dry heat loss'.

6 0

2 years ago

Determine the mass, in grams, of 0.350 moles of s (1 mol of s has a mass of 32.07 g).

hram777 [196]

Answer:

11.22 gm

Explanation:

32.07 gm / mole * .350 mole = 11.22 gm

4 0

1 year ago

What is the total number of valence electrons in a carbon atom in the ground state

kolbaska11 [484]

Carbon will have 4 valence electrons. It will have 2 in the p orbital and 2 in the s orbital. You can see this when you find the noble gas configuration of carbon which is [He]2s²2p² showing that carbon has 4 valence electrons.
I hope this helps. Let me know if anything is unclear.

6 0

2 years ago

A 3.00-kg block of copper at 23.0°C is dropped into a large vessel of liquid nitrogen at 77.3 K. How many kilograms of nitrogen

hammer [34]

Answer:

1.2584kg of nitrogen boils.

Explanation:

Consider the energy balance for the overall process. There are not heat or work fluxes to the system, so the total energy keeps the same.

For the explanation, the 1 and 2 subscripts will mean initial and final state, and C and N2 superscripts will mean copper and nitrogen respectively; also, liq and vap will mean liquid and vapor phase respectively.

The overall energy balance for the whole system is:

$U_1=U_2$

The state 1 is just composed by two phases, the solid copper and the liquid nitrogen, so: $U_1=U_1^C+U_1^{N_2}$

The state 2 is, by the other hand, composed by three phases, solid copper, liquid nitrogen and vapor nitrogen, so:

$U_2=U_2^C+U_{2,liq}^{N_2}+U_{2,vap}^{N_2}$

So, the overall energy balance is:

$U_1^C+U_1^{N_2}=U_2^C+U_{2,liq}^{N_2}+U_{2,vap}^{N_2}$

Reorganizing,

$U_1^C-U_2^C=U_{2,liq}^{N_2}+U_{2,vap}^{N_2}-U_1^{N_2}$

The left part of the equation can be written in terms of the copper Cp because for solids and liquids Cp≅Cv. The right part of the equation is written in terms of masses and specific internal energy:

$m_C*Cp*(T_1^C-T_2^C)=m_{2,liq}^{N_2}u_{2,liq}^{N_2}+m_{2,vap}^{N_2}u_{2,vap}^{N_2}-m_1^{N_2}u_1^{N_2}$

Take in mind that, for the mass balance for nitrogen, $m_1^{N_2}=m_{2,liq}^{N_2}+m_{2,vap}^{N_2}$ ,

So, let's replace $m_1^{N_2}$ in the energy balance:

$m_C*Cp*(T_1^C-T_2^C)=m_{2,liq}^{N_2}u_{2,liq}^{N_2}+m_{2,vap}^{N_2}u_{2,vap}^{N_2}-m_{2,liq}^{N_2}u_1^{N_2}-m_{2,vap}^{N_2}u_1^{N_2}$

So, as you can see, the term $m_{2,liq}^{N_2}u_{2,liq}^{N_2}$ disappear because $u_{2,liq}^{N_2}=u_{1,liq}^{N_2}$ (The specific energy in the liquid is the same because the temperature does not change).

$m_C*Cp*(T_1^C-T_2^C)=m_{2,vap}^{N_2}u_{2,vap}^{N_2}-m_{2,vap}^{N_2}u_1^{N_2}$

$m_C*Cp*(T_1^C-T_2^C)=m_{2,vap}^{N_2}(u_{2,vap}^{N_2}-u_1^{N_2})$

The difference $(u_{2,vap}^{N_2}-u_1^{N_2})$ is the latent heat of vaporization because is the specific energy difference between the vapor and the liquid phases, so:

$m_{2,vap}^{N_2}=\frac{m_C*Cp*(T_1^C-T_2^C)}{(u_{2,vap}^{N_2}-u_1^{N_2})}$

$m_{2,vap}^{N_2}=\frac{3kg*0.092\frac{cal}{gC} *(296.15K-77.3K)}{48.0\frac{cal}{g}}\\m_{2,vap}^{N_2}=1.2584kg$

3 0

3 years ago

Carbon dioxide gas reacts with liquid water to produce aqueous carbonic acid.” Which chemical equation correctly translates this

r-ruslan [8.4K]

Last option:
CO2 (g) + H2O (l) -> H2CO3 (aq)

In the brackets:
g = gas,
l = liquid,
s = solid,
aq = aqueous.

So,
CO2 (g) = carbon dioxide gas
H2O (l) = liquid water
H2CO3 (aq) = aqueous carbonic acid

7 0

2 years ago