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lesya692 [45]
3 years ago
12

What is physical evidence

Chemistry
1 answer:
postnew [5]3 years ago
3 0

Answer:

Physical evidence is any and all objects that can establish that a crime has been committed or can provide a link between a crime and its victim or perpetrator. ... Physical evidence aids in the solution of a case, provides an element of the crime, such as fear or force, and proves a theory in the case.

Explanation:

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List three aids with example that are useful for people who are optically impaired​
fomenos
Magnifying Glasses, Telescopes and Glasses.
8 0
3 years ago
If 13.7 grams of manganese oxide reacts with excess hydrogen chloride gas, how many grams of water are formed?
Lerok [7]

Answer:

5.67 g OF WATER WILL BE FORMED WHEN 13.7 g OF MnO2 REACTS WITH HCl GAS.

Explanation:

EQUATION FOR THE REACTION

Mn02 + 4HCl --------> MnCl2 + Cl2 + 2H2O

From the balanced reaction between manganese oxide and hydrogen chloride gas;

1 mole of MnO2 reacts to form 2 mole of water

At STP, the molecular mass of the sample is equal to the mole of the substance. So therefore:

(55 + 16 * 2) g of MnO2 reacts to form 2 * ( 1 *2 + 16) g of water

(55 + 32) g of MnO2 reacts to form 2 * 18 g of water

87 g of MnO2 reacts to form 36 g of water

If 13.7 g of MnO2 were to be used?

87 g of MnO2 = 36 g of H2O

13.7 g of MnO2 = ( 13.7 * 36 / 87) g of water

= 493.2 / 87 g of water

Mass of water = 5.669 g of water

Approximately 5.67 g of water will be formed when 13.7 g of manganese oxide reacts with excess hydrogen chloride gas.

3 0
3 years ago
ANSWER THESE 5 MULTPLE CHOICE QUESTIONS!!!<br> I'LL GIVE 30 POINTS AND A BRAINIEST:)
mestny [16]

Answer: 1, magnesium & mg

2, two energy shells

Explanation:

3 0
2 years ago
Read 2 more answers
A student ran the following reaction in the laboratory at 671 K: 2NH3(g) N2(g) + 3H2(g) When she introduced 7.33×10-2 moles of N
vaieri [72.5K]

Answer:

Kc = 8.05x10⁻³

Explanation:

This is the equilibrium:

                 2NH₃(g)   ⇄     N₂(g)     +     3H₂(g)

Initially       0.0733

React         0.0733α          α/2                3/2α

Eq     0.0733 - 0.0733α    α/2                0.103

We introduced 0.0733 moles of ammonia, initially. So in the reaction "α" amount react, as the ratio is 2:1, and 2:3, we can know the moles that formed products.

Now we were told that in equilibrum we have a [H₂] of 0.103, so this data can help us to calculate α.

3/2α = 0.103

α = 0.103 . 2/3 ⇒ 0.0686

So, concentration in equilibrium are

NH₃ = 0.0733 - 0.0733 . 0.0686 = 0.0682

N₂ = 0.0686/2 = 0.0343

So this moles, are in a volume of 1L, so they are molar concentrations.

Let's make Kc expression:

Kc= [N₂] . [H₂]³ / [NH₃]²

Kc = 0.0343 . 0.103³ / 0.0682² = 8.05x10⁻³

3 0
3 years ago
Calculate the equilibrium constant for the reaction using the balanced chemical equation and the concentrations of the substance
Oliga [24]

Answer:

4.75 is the equilibrium constant for the reaction.

Explanation:

CO(g)+H_2O(g)\rightleftharpoons CO_2(g)+H_2(g)

Equilibrium concentration of reactants :

[CO]=0.0590 M,[H_2O]=0.00600 M

Equilibrium concentration of products:

[CO_2]=0.0410 M,[H_2]=0.0410 M

The expression of an equilibrium constant is given by :

K_c=\frac{[CO_2][H_2]}{[CO][H_2O]}

K_c=\frac{0.0410 M\times 0.0410 M}{0.0590M\times 0.00600 M}

K_c=4.75

4.75 is the equilibrium constant for the reaction.

3 0
3 years ago
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