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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.
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The enthalpy change for the reaction of titanium metal with gaseous iodine is given by the following thermochemical equation: 2
julia-pushkina [17]

Answer : The enthalpy change for the reaction is, 419.5 kJ

Explanation :

According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.

The given chemical reaction is,

2Ti(s)+3I_2(g)\rightarrow 2TiI_3(s)    \Delta H=-839kJ

Now we have to determine the enthalpy change for the reaction below:

TiI_3(s)\rightarrow Ti(s)+\frac{3}{2}I_2(g)    \Delta H'=?

By reversing and then dividing the reaction by 2, we get the enthalpy change for the reaction.

The expression will be:

\Delta H'=-\frac{(\Delta H)}{2}

\Delta H'=-\frac{(-839kJ)}{2}

\Delta H'=419.5kJ

Therefore, the enthalpy change for the reaction is, 419.5 kJ

3 0
3 years ago
HClO4+P4O10=H3PO4+Cl2O7 how do you balance this?
Tom [10]

12 HClO₄ + 1 P₄O₁₀ → 4 H₃PO₄ + 6 Cl₂O₇

<h3>Explanation</h3>

Balance by the conservation of atoms.

Assign coefficient <em>1 </em>to the species with the largest number of elements and atoms. H₃PO₄ contains three elements. Each of its molecule contains eight atoms, that's two more than the six atoms in a HClO₄ molecule. Start by assigning H₃PO₄ a coefficient of <em>1</em>.

? HClO₄ + ? P₄O₁₀ → <em>1</em> H₃PO₄ + ? Cl₂O₇

There are now three H atoms, one P atom on the product side. H₃PO₄ is the only product that contains H and P atoms. As a result, there should be the same number of H and P atoms on the reactant side.

  • Among all reactants, only HClO₄ contains H atoms. Each HClO₄ molecule contains one H atom. Three H atoms correspond to three HClO₄ molecule.
  • Among all reactants, only P₄O₁₀ contains P atoms. Each P₄O₁₀ molecule contains four P atoms. One P atom corresponds to 1/4 of a P₄O₁₀ molecule.

Thus

<em>3</em> HClO₄ + <em>1/4</em> P₄O₁₀ → <em>1</em> H₃PO₄ + ? Cl₂O₇

There are three Cl atoms in three HClO₄ molecules. HClO₄ is the only species that contains Cl among all reactants. There are three Cl atoms on the reactant side and shall be the same number of Cl atoms on the product side.

  • Cl₂O₇ is the only molecule that contains Cl among the products. Each Cl₂O₇ molecule contains two Cl atoms. Three Cl atoms will correspond to 3/2 Cl₂O₇ molecules.

<em>3</em> HClO₄ + <em>1/4</em> P₄O₁₀ → <em>1</em> H₃PO₄ + <em>3/2</em> Cl₂O₇

Multiply both sides by the least common multiple of the denominators to eliminate the fraction. The least common multiple in this case is four.  

12 HClO₄ + 1 P₄O₁₀ → 4 H₃PO₄ + 6 Cl₂O₇

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3 years ago
Use the periodic table to answer this question. Decomposing calcium carbonate yields calcium oxide and carbon dioxide. What info
Anuta_ua [19.1K]
Atomic number and place on table.
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PLEASE HELP ASAP!!!<br> What is the mass of the element above?<br> -1<br> -2<br> -3<br> -4<br> -5
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Answer:

its 1 not negative

the atom shown below was hydrogen, known as H.

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Help me pls rawr uwu SSUsSY
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Help 2 what the answer for this?

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