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3 years ago

How is the evidence from a fire scene collected? What should be avoided?

2 answers:

5 0

Fire scenes are different than regular crime scenes because the evidence that was at the.Evidence from a fire scene is collected by being placed in an air-airtight.Plastic bags should be avoided because they can produce dangerous gases

sveticcg [70]3 years ago

3 0

Answer:

Explanation:

In fire and arson cases evidences like volatile fuel in the sediment debris can be collected. The debris should be collected in an air-tight container like tin or paint box and bottles so as to prevent the evaporation of the fuel. The type of fuel used for setting up the fire is an important evidence.

Plastic bags should not be used because the plastic can react with the fuel components and may react with the fuel components in debris and the evidence will become futile.

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Which of these phase changes does NOT involve changing a liquid into a gas?

zzz [600]

The answer is sublimation.

Sublimation is the chemical process whereby a solid turns into a gas without first becoming a liquid.

The word sublimation comes from the Latin word sublimare which means "raised to a higher status."

Examples of sublimation include surface layer of snow and ice turning into steam or fog without melting and dry ice which is the solid form of carbon dioxide which also undergoes sublimation.

The low temperature and sublimation makes dry ice an effective coolant or cooling agent . One of its main advantages is that it has a lower temperature than water ice and also does not leave any residue.

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3 years ago

The vapor pressure of liquid chloroform, CHCl3, is 100. mm Hg at 283 K. A 0.380 g sample of liquid CHCl3 is placed in a closed,

Katyanochek1 [597]

Answer:

100 mm Hg

Explanation:

From the question we are told that

The vapor pressure of CHCl3, is $P = 100 \ mmHg = \frac{100}{760}= 0.13156 \ atm$

The temperature of CHCl3 is $T = 283 \ K$

The volume of the container is $V_c = 380mL = 380 *10^{-3}\ L$

The temperature of the container is $T_c = 283 \ K$

The mass of CHCl3 is m = 0.380 g

Generally the number of moles of CHCl3 present before evaporation started is mathematically represented as

$n = \frac{m }{M }$

Here M is the molar mass of CHCl3 with the value $M = 119.38 \ g/mol$

=> $n = \frac{ 0.380 }{119.38 }$

=> $n = 0.00318 \ mols$

Generally the number of moles of CHCl3 gas that evaporated is mathematically represented as

$n_g = \frac{PV}{RT}$

Here R is the gas constant with value $R = 0.08206 L \ atm /mol\cdot K$

$n_g = \frac{0.13156* 380 *10^{-3} }{0.08206 * 283}$

$n_g = 0.00215 \ mols$

Given that the number of moles of CHCl3 evaporated is less than the number of moles of CHCl3 initially present , then it mean s that not all the liquid evaporated

At equilibrium the temperature of CHCl3 will be equal to the pressure of air so the pressure at equilibrium is 100 mmHg

4 0

2 years ago

Which is the least likely to be reduced?

Romashka-Z-Leto [24]

Answer:

The correct answer would actually be B

Explanation:

A P E X

7 0

2 years ago

H-h+cl+cl____2h-cl... calculate the energy needed to break the bond

Elenna [48]

The energy required to break one mole of Cl - Cl bond is 242 kJ/mol

4 0

3 years ago

How many grams of N2 are in 44.8L at STP?

lutik1710 [3]

Answer: 10 i think

Explanation:

3 0

3 years ago