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3 years ago

In an electrically neutral atom of any element, there are equal numbers of

Chemistry

1 answer:

Masteriza [31]3 years ago

8 0

Answer:

B. electrons and protons.

Explanation:

In an electrically neutral atom of any element, there are equal number of protons and electrons in the atom.

Protons are the positively charged particles in an atom.

Electrons are the negatively charged particles within the atom.

When the number of protons and electrons are the same or equal, the atom is neutral.

But when there is an imbalance, an ion results.

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daser333 [38]

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4 0

3 years ago

An environmental scientist developed a new analytical method for the determination of cadmium (cd^2+) in mussels. To validate th

Anettt [7]

Answer:

The method is accurate in the calculation of the $Cu^+2$

Explanation:

As a first step we have to calculate the average concentration of $Cu^+2$ find it by the method.

$\frac{0.782+0.762+0.825+0.838+0.761 }{5} =0.79 ppm$

Then we have to find the standard deviation:

$s=\sqrt{\frac{1}{N-1}\sum_{i=1}^N(x_i-\bar{x})^2}=0.0359$

For the confidence interval we have to use the formula:

μ=Average± $\frac{t*s}{\sqrt{n} }$

Where:

t=t student constant with 95 % of confidence and 5 data=2.78

μ= $0.79$ ± $\frac{2.78*0.0359}{\sqrt{5} }$

upper limit: 0.84

lower limit: 0.75

If we compare the limits of the value obtanied by the method (Figure 1 Red line) with the reference material (Figure 1 blue line) we can see that the values obtained by the method are within the values suggested by the reference material. So, it's method is accurate.

7 0

3 years ago

Write a balanced equation for the complete combustion of each compound. a. formaldehyde (CH2O(g)) b. heptane (C7H17(l)) c. benze

Yuri [45]

Answer:

a. formaldehyde (CH₂O(g)): CH₂O(g) + O₂(g) → CO₂(g) + H₂O(g)

b. heptane (C₇H₁₇(l)): 4C₇H₁₇(l) + 45O₂(g) → 28CO₂(g) + 34H₂O(g)

c. benzene (C6H6(l)): C₆H₆(l) + 15/2 O₂(g) → 6CO₂(g) + 3 H₂O(g)

Explanation:

In a reaction of combustion, a hydrocarbon compound (composed of C, H and O) reacts with oxygen gas (O₂). The complete combustion of a hydrocarbon - such as formaldehyde, heptane, and benzene - produces carbon dioxide (CO₂) and water (H₂O).

Thus, we write the reactants and products for each combustion reaction and then we balance the atoms: C, H, and O.

a. formaldehyde (CH₂O(g)):

CH₂O(g) + O₂(g) → CO₂(g) + H₂O(g)

The chemical equation is already balanced with the coefficients 1: we have the same number of C atoms (1), H (2) and O (3) on both sides of the equation.

b. heptane (C₇H₁₇(l)):

C₇H₁₇(l) + O₂(g) → CO₂(g) + H₂O(g)

Here we have to write a coefficient 28 for CO₂ to balance the C atoms in the products side, and for C₇H₁₇ we write 28/4 = 7. With similar reasoning we found the coefficients for O₂ and H₂O:

4C₇H₁₇(l) + 45O₂(g) → 28CO₂(g) + 34H₂O(g)

c. benzene (C6H6(l)):

C₆H₆(l) + O₂(g) → CO₂(g) + H₂O(g)

First, we write a coefficient of 6 for CO₂ to balance the C atoms. Then, we have to balance H atoms: we write a coefficient 3 in H₂O. Now, we have 12 + 3 = 15 atoms of O on the reactants side. So, we write a half of these number of atoms in the coefficient for O₂: 15/2. We obtain the balanced equation:

C₆H₆(l) + 15/2 O₂(g) → 6CO₂(g) + 3 H₂O(g)

5 0

2 years ago

Which element has a complete valence electron shell? selenium (Se) oxygen (O) fluorine (F) argon (Ar)

kirill115 [55]

Answer:

oxygen (O)

Explanation:

3 0

3 years ago

Read 2 more answers

Balance this chemical equation Cu(OH)2+ HCl --> CuCl2 + H2O