## Energy Balance

### GATE-CH-2001-1-5-pc-1mark

2001-1-5-pc

For the case of fuel gas undergoing combustion with air, if the air/fuel ratio is increased, the adiabatic flame temperature will

• increase
• decrease
• increase or decrease depending on the fuel type
• not change

### GATE-CH-2003-4-pc-1mark

2003-4-pc

For estimation of heat capacity of a solid compound, one can use

• Clapeyron's equation
• Gibb's equation
• Kopp's rule
• Trouton's rule

### GATE-CH-1991-2-iv-pc-2mark

1991-2-iv-pc

The heat absorbed (in kJ/mol) for isothermal reaction (given below) at 298 K and 1 atm pressure is ––––- $\ce {C4H10(g)} \rightarrow \ce {C2H4(g)} + \ce {C2H6(g)}$ Standard heat of combustion, kJ/mol:
$$\ce {C4H10(g)}$$ = $$-2873.5$$; $$\ce {C2H4(g)}$$ = $$-1411.9$$; $$\ce {C2H6(g)}$$ = $$-1561.0$$.

### GATE-CH-1999-1-5-pc-2mark

1999-1-5-pc

A solution of specific gravity 1.0 consists of 35% $$A$$ by weight and the remaining $$B$$. If the specific gravity of $$A$$ is 0.7, the specific gravity of $$B$$ is

• 1.25

• 1.3

• 1.35

• 1.2

### GATE-CH-2003-39-pc-2mark

2003-39-pc

An aqueous solution of 2.45% by weight H2SO4 has a specific gravity of 1.011. The composition expressed in normality is

• 0.2500
• 0.2528
• 0.5000
• 0.5055

[Index]

### GATE-CH-2005-41-pc-2mark

2005-41-pc

A metal recovery unit (MRU) of intake capacity 5000 kg/h treats a liquid product from a plant and recovers 90% of the metal in pure form. The unrecovered metal and its associated liquid are sent to a disposal unit along with the untreated product from the plant (See figure below). Find the flow rate ($$m_6$$) and the weight fraction of the metal ($$w_6$$). The liquid product flow rate is 7500 kg/h of composition 0.1 (wt fraction). Assume steady state.

• $$m_6=7500$$ kg/h, $$w_6=0.0$$
• $$m_6=7050$$ kg/h, $$w_6=0.04255$$
• $$m_6=4500$$ kg/h, $$w_6=0.1712$$
• $$m_6=5600$$ kg/h, $$w_6=0.0314$$

### GATE-CH-2009-28-pc-2mark

2009-28-pc

Pure water (stream $$W$$) is to be obtained from a feed containing 5 wt% salt using a desalination unit as shown below.

If the overall recovery of pure water (through stream $$W$$) is 0.75 kg/kg feed, then the recycle ratio ($$R/F$$) is

• 0.25

• 0.50

• 0.75

• 1.00

### GATE-CH-0100-5-pc-2mark

0100-5-pc

A tank contains 1000 liter of brine with 15 kg of dissolved salt. Pure water enters the tank at a rate of 10 liter per min. The solution is kept thoroughly mixed and drains from the tank at the same rate. How much salt (in kg) is in the tank, after 20 minutes?

### GATE-CH-1989-1-ii-pc-2mark

1989-1-ii-pc

100 m$$^3$$ of a gas mixture containing 10% $$A$$ and 90% $$B$$ is to be enriched to contain 40% $$A$$ by mixing with pure $$A$$ at constant pressure and temperature. All compositions are in volume %. The amount of pure $$A$$ added is ––––- m$$^3$$.

### GATE-CH-1989-11-i-pc-3mark

1989-11-i-pc

A 4% solution of a salt in water is required in a continuous process. For this purpose, a part of the water is by passed through a saturator from which a 25% solution is produced. If this stream is mixed with the main water stream to produce the 4% solution, what percentage of water must be by passed?

[Index]

### GATE-CH-1992-11-pc-6mark

1992-11-pc

The concentration of $$\ce {SO2}$$ in the flue gases from a boiler was found to be 0.2 kg/m$$^3$$ at N.T.P. Determine the concentration of $$\ce {SO2}$$ in parts per million by volume, at N.T.P. Assume that the flue gases are perfect.

### GATE-CH-1997-12-pc-5mark

1997-12-pc

Sea water is desalinated by reverse osmosis as shown in figure.

All compositions are on mass basis. Calculate $$R/E$$.

### GATE-CH-2013-48-49-pc-4mark

2013-48-49-pc

A reverse osmosis unit treats feed water $$(F)$$ containing fluoride and its output consists of a permeate stream $$(P)$$ and a reject stream $$(R)$$. Let $$C_F, C_P$$, and $$C_R$$ denote the fluoride concentrations in the feed, permeate, and reject streams, respectively. Under steady state conditions, the volumetric flow rate of the reject is 60% of the volumetric flow rate of the inlet stream, and $$C_F = 2$$ mg/L and $$C_P = 0.1$$ mg/L.

(i) The value of $$C_R$$ in mg/L, up to one digit after the decimal point, is ____________

{#1}

(ii) A fraction $$f$$ of the feed is bypassed and mixed with the permeate to obtain treated water having a fluoride concentration of 1 mg/L. Here also the flow rate of the reject stream is 60% of the flow rate entering the reverse osmosis unit (after the bypass). The value of $$f$$, up to 2 digits after the decimal point, is ____________

{#2}

[Index]