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Elina [12.6K]
3 years ago
5

Which can associate a suspect and the firing of a gun?

Chemistry
1 answer:
baherus [9]3 years ago
5 0
D. powder residues.
the police and forensic chemists usually perform a qualitative test called GPR or gun powder residue. the residue sticks to the skin.
You might be interested in
Dalton law states that the partial pressure of a gas in a mixture of gases is _____ to the total pressure of the mixture.
OLEGan [10]

Answer:

Dalton law states that the partial pressure of a gas in a mixture of gases is equal to the total pressure of the mixture.

4 0
2 years ago
Can someone help me with this
topjm [15]

Answer: It would be malleable, solids, luster, conductors, reactive

Explanation:

8 0
3 years ago
Read 2 more answers
A Review Constants Periodic Table
soldi70 [24.7K]

Answer:

C. 1, 4–dimethyl–1–cyclohexene

D. 4, 6–dichloro–1–heptene

Explanation:

C. Determination of the name of the compound.

To name the compound given above we must observe the following:

1. Determine the functional group of the compound. In this case, the functional group is the double bond (–C=C–).

2. Determine the parent name by counting the number of carbon that makes up the ring. In this case, 6 carbon makes up the ring. Hence the parent name is cyclohexene.

3. Identify the substituent group attached to the compound. In this case, two methyl group i.e –CH₃ are attached.

4. Locate the position of the substituent group attached by giving the functional group the lowest possible count. In this case, the functional group is at carbon 1, the first methyl group is at carbon 1 and the 2nd methyl group is at carbon 4.

5. Combine the above to obtain the name. Thus, the name of the compound is:

1, 4–dimethyl–1–cyclohexene.

D. Determination of the name of the compound.

To name the compound given above we must observe the following:

1. Determine the functional group of the compound. In this case, the functional group is the double bond (–C=C–).

2. Determine the parent name by counting the number of carbon that makes up the chain. In this case, 7 carbons makes up the chain. Hence, the parent name of the compound is heptene.

3. Identify the substituent group attached to the compound. In this case, two chlorine (Chloro) i.e –Cl are attached.

4. Locate the position of the substituent group attached by giving the functional group the lowest possible count. In this case, the functional group is at carbon 1, the first chlorine is at carbon 4 and the 2nd is at carbon 6.

5. Combine the above to obtain the name. Thus, the name of the compound is:

4, 6–dichloro–1–heptene

8 0
2 years ago
100 PIONTSSSSS HELP ASAP
valina [46]

Left Panel

Short answer A

<em><u>Solution</u></em>

Since you have been given choices, my sloppy numbers will do, but it anyone is going to see this, YOU SHOULD CLEAN  THEM UP WITH THE NUMBERS THAT COME FROM YOUR PERIODIC TABLE.

Equation

Sodium Phosphate + Calcium Chloride ===> Sodium Chloride + Calcium Phosphate.

Na3PO4 + CaCl2 ===> NaCl + Ca3(PO4)2

<em><u>Step One</u></em>

Balance the Equation

2Na2PO4 + 3CaCl2 ==> 6NaCl + Ca3(PO4)2

<em><u>Step Two</u></em>

Find the molar mass of CaCl2

Ca = 40

2Cl = 71

Molar Mass = 40 + 71 = 111 grams/mole

<em><u>Step Three</u></em>

Find the number of moles of CaCl2

Given mass = 379.4

Molar Mass = 111

moles = given Mass / molar Mass

moles of CaCl2 = 379.4/111 = 3.418 moles

<em><u>Step Four</u></em>

Find the number of moles of Ca3(PO4)2 needed.

This requires that you use the balance numbers from the balanced equation.

For every 3 moles of CaCl2 you have, you get 1 mole of Ca3(PO4)2

n_moles of Ca3(PO4)2 = 3.418 / 3 = 1.13933 moles

<em><u>Step Five</u></em>

Find the molar mass of Ca3(PO4)2

From the periodic table,

3Ca = 3 * 40 = 120

2 P  = 2 * 31 =    62

8 O = 8 * 16   =128

Molar Mass = 120 + 62 + 128= 310 grams per mole.

<em><u>Step Six</u></em>

1 mole of Ca3(PO4)2 has a molar mass of 310 gram

1.13933 moles of Ca3(PO4)2 = x

x = 1.13933 moles * 310 grams /mole

x = 353.2 grams. As you can see, even with my rounding I'm only out 0.3 of a gram. DON'T FORGET TO PUT THIS TO THE PROPER SIG DIGS IF SOMEONE ELSE IS GOING TO SEE IT.

Middle Panel

Short Answer C

Equation

2HCl + Mg ===> H2 + MgCl2

The object of the first part of the game is to find the number of moles of H2.

<em><u>Step One</u></em>

Find the moles of HCl

1 mole HCl = 35.5 + 1 = 36.5

n = given mass divided by molar mass

n = 49 grams / 36.5 = 1.34 moles.

The balanced equation tells you that for ever mole of H2 produced, you need 2 moles of HCl. That's what the balance numbers are for.

So the number of moles of H2 is 1.34 / 2 = 0.671 moles of H2.

Now we come to Part II. We have to use an new friend of yours that I have seen only once before from you.

Find V using PV = nRT

R is going to be in kPa so the value of R = 8.314

V = ???

n = 0.671 moles

T = 25 + 273 = 298oK

P = 101.3 kPa

101.3 * V= 0.671*8.314 * 298

V = 0.671 * 8.314 * 298 / 101.3

V = 16.4

The answer is C and again, I have rounded almost everything except R, although it can go out to 8 places.

Right Panel

I can't see the panel. I don't know what the problem is. Never mind I got it. I'm going to be a little skimpy on this one since I've done two like it and they are long.

LiOH + HBr ===> LiBr + H2O and the equation is balanced.

You have to figure out the moles of LiOH and HBr. Use the LOWEST number of moles

n_LiOH = given mass / molar mass = 117/(7 + 16 + 1) = 117 / 24 = 4.875 moles

n_HBr = given mass / molar mass =  141/(1 + 80) = 141 / 81 = 1.741 moles

HBr is the lower number. That's all the LiBr you are going to get is 1.741. There is no adjustment to be made from the balance equation.

n = given mass / molar mass  multiply both sides by the molar mass

n * Molar mass (LiBr) = n * (7 + 80) = 1.741 * 87 = 151 grams of

The answer is C


6 0
2 years ago
If enough changes occur in the gene pool of a species, it is possible that a new species would be created.
lianna [129]

Answer:

Yes

Explanation:

A gene pool is the sum total of all the genes(sum of alleles)of a species and population at any given time is known as gene pool.

The new species are created in nature by four mechanisms such as geographic isolation (allopatric speciation), reproductive isolation (sympatric speciation), mating behaviour (parapatric speciation).

Due to any of these factors when population acquire unique changes in their genes and enough changes have been introduced in the gene pool of the population with time, two population become distinct from each other and not able to interbreed leads to the formation of new species.

6 0
3 years ago
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