How you could use the scientific method to learn whether water really does take longer to boil if you are watching it.

The reducing agent in the reaction described in Fe + 2HCl → FeCl2 + H2 is A. H2. B. Fe. C. HCl. D. FeCl2.

Fed [463]

The reducing agent is b). Fe

7 0

3 years ago

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Which statement about Fe is supported by the modern atomic theory but not John Dalton’s theory?

lana66690 [7]

Answer:

The correct option is B

Explanation:

One of the claims of John Dalton's atomic theory is that atom is the smallest unit of matter (which suggests that there are no particles smaller than an atom in any matter). This claim has been disproved by the modern atomic theory which established that there are particles smaller than atom (called subatomic particles). These particles are electrons, protons and neutrons.

One of the modern atomic theory was by Neils Bohr, who proposed that electrons move in circular orbits around the central nucleus. Thus, the electrons of iron can also be said to be present in a region of space (circular path) around the nucleus. This proves that option B is the correct option as John Dalton's theory did not even recognize the electron(s) nor the nucleus.

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3 years ago

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Drinking water may contain a low concentration of lead ion (Pb2 ) due to corrosion of old lead pipes. The EPA has determined tha

Lynna [10]

Answer:

3.861x10⁻⁹ mol Pb⁺²

Explanation:

We can define ppm as mg of Pb²⁺ per liter of water.

We calculate the mass of lead ion in 100 mL of water:

100.0 mL ⇒ 100.0 / 1000 = 0.100 L

0.100 L * 0.0080 ppm = 8x10⁻⁴ mg Pb⁺²

Now we convert mass of lead to moles, using its molar mass:

8x10⁻⁴ mg ⇒ 8x10⁻⁴ / 1000 = 8x10⁻⁷ g

8x10⁻⁷ g Pb²⁺ ÷ 207.2 g/mol = 3.861x10⁻⁹ mol Pb⁺²

4 0

3 years ago

(a)-Use Lewis symbol store present there action that occurs between Ca and F atoms. (b)-What is the chemical formula of the most

Charra [1.4K]

Answer:

(a) The Lewis structure is shown in the image below.

(b) $CaF_2$

(c) Calcium loses 2 electrons to 2 atoms of fluorine and these 2 atoms of fluorine accepts each electron to form ionic bond.

(d) Calcium atom loses electrons.

Explanation:

Calcium is the element of second group and forth period. The electronic configuration of Calcium is - 2, 8, 8, 2 or $1s^22s^22p^63s^23p^64s^2$

There are 2 valence electrons of Calcium.

Fluorine is the element of group 17 and second period. The electronic configuration of the element fluorine is - 2, 7 or $1s^22s^22p^5$

There is 1 valence electron of fluorine.

The Lewis structure is drawn in such a way that the octet of each atom is complete.

Thus, calcium loses 2 electrons to 2 atoms of fluorine and these 2 atoms of fluorine accepts each electron to form ionic bond. This is done in order that the octet of the atoms are complete and they become stable.

Thus, the formula of calcium chloride is $CaF_2$ .

(a) The Lewis structure is shown in the image below.

(b) $CaF_2$

(c) Calcium loses 2 electrons to 2 atoms of fluorine and these 2 atoms of fluorine accepts each electron to form ionic bond.

(d) Calcium atom loses electrons.

5 0

2 years ago

Your computer is an example of which type of energy? Question options: Nuclear Kinetic Light All of the above

xz_007 [3.2K]

Answer: Light

Computer is an example of light energy which is the third option out of the given four choices. 

Explanation:

We know how a computer works it takes in the electrical energy and does a lot of mathematical mechanical work and for giving answers. It uses a screen on which light blinks in pattern such that it represents letters or mathematical numbers or expressions.

Hence by using this statement we can say computer converts electrical energy into light energy. 

4 0

3 years ago