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3 years ago

3. The opening that allows light to enter the eye is the

Chemistry

2 answers:

AlexFokin [52]3 years ago

5 0

Answer:

A. The opening that allows light to enter the eye is the iris.

Explanation:

xxMikexx [17]3 years ago

4 0

Answer:

A) Iris

Explanation:

The Iris controls the diameter of the opening in your eye, thus also controlling the amount of light let inside. It's also reponsible for the colour of you eye.

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What is the value of delta Hrxn for this equation:

Ratling [72]

Answer:

The ΔHrxn for the above equation = 179 kJ/mol

Explanation:

The reaction bond enthalpies are for the reactant;

3 × N-H = 3 × 390 = 1,170 kJ/mol

2 × O=O = 2 × 502 = 1004 kJ/mol

The reaction bond enthalpies are for the product;

3 × N-O = 3 × 201 = 603 kJ/mol

3 × O-H = 3 × 464 = 1,392 kJ/mol

The ΔHrxn for the above equation is therefore;

ΔHrxn = 1,170 + 1,004 - (603 + 1,392) = 179 kJ/mol

6 0

2 years ago

1 Calcium carbonate breaks down on heating to produce calcium oxide and carbon dioxide gas.

Alborosie

Answer: See below

Explanation:

1. a) 0.15 moles calcium carbonate (15g/100g/mole)

b) 0.15 moles CaO (molar ratio of CaO to CaCO3 is 1:1)

c) 8.4 grams CaO (0.15 moles)*(56 grams/mole)

2. a) 0.274 moles Na2O (17g/62 grams/mole)

b) 46.6 grams NaNO3 (2 moles NaNO3/1 mole Na2O)*(0.274 moles Na2O)*(85 g/mole NaNO3)

7 0

3 years ago

A ping pong ball with a mass of 2.20 grams rolls along a frictionless table with a velocity of 0.850 m/s. what is the momentum o

Nataly_w [17]

1.87 should be your answer

6 0

3 years ago

Read 2 more answers

Muriatic acid, HCl, is often used to remove rust. A solution of muriatic acid, HCl, reacts with Fe2O3 deposits on industrial equ

Alina [70]

Answer:

Explanation:

Step 1:

The balanced equation for the reaction.

Fe2O3(s) + 6HCl(aq) → 2FeCl3(aq) + 3H2O

Step 2 :

Determination of the masses of HCl and Fe2O3 that reacted from the balanced equation. This is illustrated below:

Molar mass of Fe2O3 = 159.70g/mol

Molar mass of HCl = 36.46 g/mol

Mass of HCl from the balanced equation = 6 x 36.46 = 218.76g

From the balanced equation above,

159.70g of Fe2O3 reacted with 218.76g of HCl

Step 3:

Determination of the mass of HCl needed to react with 439g of Fe2O3. This is illustrated below:

From the balanced equation above,

159.70g of Fe2O3 reacted with 218.76g of HCl.

Therefore, 439g of Fe2O3 will react with = (439 x 218.76) /159.70 = 601.35g of HCl.

Step 4:

Conversion of 601.35g of HCl to mole. This is illustrated below:

Molar mass of HCl = 36.46 g/mol

Mass of HCl = 601.35g

Number of mole = Mass/Molar Mass

Number of mole of HCl = 601.35/36.46

Number of mole of HCl = 16.49 moles

Step 5:

Determination of the volume of the HCl that reacted.

This is illustrated below:

Mole of HCl = 16.49 moles

Molarity of HCl = 5.50 M

Volume =?

Molarity = mole /Volume

Volume = mole /Molarity

Volume = 16.49/5.5

Volume of HCl = 3L

Therefore the volume of HCl needed for the reaction is 3L

5 0

2 years ago

A magnesium ion, Mg2+, is formed from a magnesium atom, Mg.

konstantin123 [22]

Answer:

The correct row is B.

Explanation:

The formation of the magnesium ion, Mg²⁺, comes from the removal of 2 electrons from the valence shell of the magnesium atom.<em> </em>Since the remotion is of electrons, the nucleus of the atom remains the same, so the number of protons and the number of neutrons does not change.<em> </em>

If the number of proton change, then the atom also change, since the identity of an atom is related to the atomic number which is the same to the proton number.

Now, if the number of neutrons changes, then we would be in the presence of an isotope of the magnesium atom.

Therefore, the correct row is B.

I hope it helps you!

5 0

3 years ago