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3 years ago

The illuminance on a surface is 6 lux and the surface is 4 meters from the light source. What is the intensity of the source?

Chemistry

2 answers:

Elza [17]3 years ago

7 0

The correct answer is:

D. 96 candelas

Ghella [55]3 years ago

3 0

Answer: D. 96 candelas

Explanation: Illuminance is defined as the quantity of light incident on a surface per unit of area. It depends on the light’s intensity and its distance from the surface.

E= illuminance on the surface (in lux)= 6 lux

I = the intensity of the light from the source (in candelas) = ?

S= distance from the light source to the surface (in meters) = 4 m

$E=\frac{I}{S^2}$

$I=E\times S^2$

$I=6\times (4)^2=96candela$

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Answer:

D. The number of it's protons

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3 years ago

. Which of the following is NOT the basic patterns of crystalline structure?

HACTEHA [7]

Answer:

c) Hexagonal close packed

Explanation:

The fact that a material is crystalline, amorphous or semicrystalline defines some of its properties. For example, if a material had the option of being crystalline or amorphous, it would be observed that in the crystalline state the density of the material would be greater in the amorphous state. This is because because of the order that the atoms follow in the crystalline material, it is possible to place more atoms in the same physical volume. When there are more atoms there is more mass in the same volume so the density is higher than when the material is amorphous.

The different crystalline structures are the following:

Simple cubic structures: the unit cell is a common edge cube, with a defined network point in each of its vertices.

Cubic structure centered on the body: the unit cell is a cube with a common edge. It has a defined network point in each of its vertices and a defined network point in the geometric center of the cube. INCLUDES a)

Cubic structure centered on the face: the unit cell is a cube with a common edge. It has a defined network point in each of its vertices and a defined network point in the geometric center of each of its faces. INCLUDES b) and d)

4 0

3 years ago

For the following reaction, 89.5 grams of iron are allowed to react with 36.9 grams of oxygen gas. iron (s) oxygen (g) iron(III)

hodyreva [135]

Answer:

122.3 g of Fe₂O₃ is the maximum amount formed

Explanation:

Our reactants for the reaction:

89.5 g of Fe

36.9 g of O₂

We convert the mass of each to moles:

89.5 g of Fe . 1 mol / 55.85 g = 1.60 moles

36.9 g of O₂ . 1mol / 32g = 1.15 moles

The reaction is 4Fe(s) + 3O₂(g) → 2Fe₂O₃ (s)

We determine the limiting reactant:

4 moles of Iron can react with 3 moles of O₂

Therefore 1.60 moles of Iron will react with (1.60 .3) / 4 = 1.2 moles

Oxygen is the limiting reactant; we need 1.2 moles, and we only have 1.15.

Then we work with the stoichiometry again.

3 moles of oxygen can produce 2 moles of Fe₂O₃

1.15 moles of oxygen may produce (1.15 . 2) / 3 = 0.766 moles of Fe₂O₃

We convert the moles to mass: 0.766 mol . 159.7 g /1mol = 122.3 g of Fe₂O₃

4 0

3 years ago

How much heat is required to vaporize 43.9 g of acetone at its boiling point?

bogdanovich [222]

The heat required to vaporize 43.9 g of acetone at its boiling point is calculated as below

the heat of vaporization of acetone at its boiling point is 29.1 kj/mole

find the moles of acetone = mass/molar mass
= 43.9g /58 g/mol =0.757 moles

heat (Q) = moles x heat of vaporization

= 29.1 kj/mole x 0.757 moles = 22.03 kj

5 0

3 years ago

Read 2 more answers

Use the balanced equation given below to solve the following problem; Calculate the volume in liters of CO produced by the react

Elan Coil [88]

Answer: 40.3 L

Explanation:

To calculate the moles :

$\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}$