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3 years ago

what type of recording do you think would be the best method of submitting evidence to a crime lab? why?

Chemistry

2 answers:

arlik [135]3 years ago

7 0

The type of recording that is the best and most useful method of submitting evidence to a crime lab is by videography.

The videography is the type of evidence that pretty much contains everything that can be get from a recording because it has both the visual aspects and the audio aspects of the crime scene. It can be said that the videography represents the ultimate type of notes.

zhannawk [14.2K]3 years ago

6 0

Answer:

The type of recording that is the best and most useful method of submitting evidence to a crime lab is by videography.

Explanation:

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Xian drew a diagram to compare deletion mutations and substitution mutations. Which label belongs in the area marked "X"? may ch

tankabanditka [31]

Answer: (B)

Explanation: Decreases the number of bases in the sequence.

3 0

3 years ago

Read 2 more answers

Classify the following reactions: HCl(aq)+NaOH(aq)→NaCl(aq)+H2O(l)HCl(aq)+NaOH(aq)→NaCl(aq)+H2O(l) Ba(OH)2(aq)+ZnCl2(aq)→BaCl2(a

Savatey [412]

The reactions are

HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)

Ba(OH)2(aq) + ZnCl2(aq) → BaCl2(aq) + Zn(OH)2(s)

2AgNO3(aq) + Mg(s) → Mg(NO3)2(aq) + 2Ag(s)

Answer:

HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l) = Acid-base reaction

Ba(OH)2(aq) + ZnCl2(aq) → BaCl2(aq) + Zn(OH)2(s) = Precipitation reaction

2AgNO3(aq) + Mg(s) → Mg(NO3)2(aq) + 2Ag(s) = Redox reaction

Explanation:

HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l) .

The reaction above is an example of an acid-base reaction. Acid-base reaction is a chemical reaction between an acid and a base. The product is usually a salt and water. An acid dissolves in water to produce H+ ion. Hydrochloric acid is a strong acid as it is completely dissociated in water. A base dissolves in water to form hydroxide ion(OH-). The sodium hydroxide is a strong base as it completely dissociate in water. The reaction between a base and an acid can be known as a neutralization reaction.

Ba(OH)2(aq) + ZnCl2(aq) → BaCl2(aq) + Zn(OH)2(s)

The reaction above is a precipitation reaction. Precipitation reaction is a reaction where two ionic bonds or cations and anions in an aqueous solution react to form an insoluble salts. The insoluble salt formed is known as the precipitate. The reaction above is an example of a double replacement reaction. From the equation the ions replace each other depending on the cations and anions. They switch partners as both reactants lose their partners to form new partnership with a different ion. The two reactants ( Ba(OH)2 and ZnCl2 ) are aqueous solution, they react to from a solid precipitates( Zn(OH)2(s) ).

2AgNO3(aq) + Mg(s) → Mg(NO3)2(aq) + 2Ag(s)

The reaction is known as an oxidation-reduction reaction(Redox reaction). A oxidation-reduction reaction their is a transfer of electron(s) between two species. The oxidation number of a chemical reaction changes by losing or gaining electrons. One of the reactant is a reducing agent and the other is an oxidizing agent.

From the reaction Mg is the reducing agent and AgNO3 is the oxidizing agents.

2 Ag+ + 2 e- → 2 Ag∧0 (reduction)

Mg∧0 - 2 e- → Mg²+ (oxidation)

8 0

3 years ago

Identify the acids and the bases in the chemical equation

agasfer [191]

<h3><u>Answer;</u></h3>

Acids; HCl and HC5H5N+

Bases; C5H5N and Cl-

<h3><u>Explanation;</u></h3>

According to Bronsted-Lowry Theory an acid is a proton or hydrogen ion donor while a base is a proton or a hydrogen ion acceptor.
In this case,<u> both HCl and HC5H5N+ are acids</u> as <u>they are donors of hydrogen ions</u>. HCl is an acid to the forward reaction while HC5H5N+ is a acid to the reverse reaction.
On the other hand, <u>C5H5N and Cl- are bases</u>, <u>they are acceptors of hydrogen ions</u>. Cl- is a base in the reverse reaction while C5H5N is a base in the forward reaction.

8 0

3 years ago

When thermal energy is removed from matter, what happens to the molecules?

Colt1911 [192]

Answer:

Figure it out.

Explanation:

3 0

2 years ago

The value of Ka for nitrous acid (HNO2) at 25 ∘C is 4.5×10−4 .a. Write the chemical equation for the equilibrium that correspond

kvv77 [185]

Answers and Explanation:

a)- The chemical equation for the corresponden equilibrium of Ka1 is:

2. HNO2(aq)⇌H+(aq)+NO−2

Because Ka1 correspond to a dissociation equilibrium. Nitrous acid (HNO₂) losses a proton (H⁺) and gives the monovalent anion NO₂⁻.

b)- The relation between Ka and the free energy change (ΔG) is given by the following equation:

ΔG= ΔGº + RT ln Q

Where T is the temperature (T= 25ºc= 298 K) and R is the gases constant (8.314 J/K.mol)

At the equilibrium: ΔG=0 and Q= Ka. So, we can calculate ΔGº by introducing the value of Ka:

⇒ 0 = ΔGº + RT ln Ka

ΔGº= - RT ln Ka

ΔGº= -8.314 J/K.mol x 298 K x ln (4.5 10⁻⁴)

ΔGº= 19092.8 J/mol

c)- According to the previous demonstation, at equilibrium ΔG= 0.

d)- In a non-equilibrium condition, we have Q which is calculated with the concentrations of products and reactions in a non equilibrium state:

ΔG= ΔGº + RT ln Q

Q= ((H⁺) (NO₂⁻))/(HNO₂)

Q= ( (5.9 10⁻² M) x (6.7 10⁻⁴ M) ) / (0.21 M)

Q= 1.88 10⁻⁴

We know that ΔGº= 19092.8 J/mol, so:

ΔG= ΔGº + RT ln Q

ΔG= 19092.8 J/mol + (8.314 J/K.mol x 298 K x ln (1.88 10⁻⁴)

ΔG= -2162.4 J/mol

Notice that ΔG<0, so the process is spontaneous in that direction.

6 0

3 years ago