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2 years ago

How does the ionosphere affect radio frequencies?

1 answer:

6 0

Due to the ability of ionized atmospheric gases to refract high frequency (HF, or shortwave) radio waves, the ionosphere can reflect radio waves directed into the sky back toward the Earth. Radio waves directed at an angle into the sky can return to Earth beyond the horizon.

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Moraines left by glaciers are different from deposits left by rivers because the rocks left behind are _____.

12345 [234]

Explanation:

unorganized and unsorted i think this is the answer

7 0

2 years ago

How many kilojoules are released when 8.2 g of water condenses at 100 °c and cools to 15 °c?

MrRa [10]

Answer:- 2.92 kJ of heat is released.

Solution:- We have water at 100 degree C and it's going to be cool to 15 degree C.

So, change in temperature, $\Delta T$ = 15 - 100 = -85 degree C

mass of water, m = 8.2 g

specific heat of water, c = $4.184\frac{J}{^0C.g}$

The equation used for solving this type of problems is:

$q=mc\Delta T$

Let's plug in the values in the equation and solve it for q which is the heat energy:

q = (8.2)(4.184)(-85)

q = -2916.248 J

They want answer in kJ. So, let's convert J to kJ and for this we divide by 1000.

$q=-2916.248J(\frac{1kJ}{1000J})$

q = -2.92 kJ

Negative sign indicates the heat is released. So, in the above process of coiling of water, 2.92 kJ of heat is released.

3 0

3 years ago

A Wisconsin farmer taps a maple tree and collects 200 liters of sap. He determines the sucrose (C12H2011) concentration to be 0.

Minchanka [31]

Answer:

6.0 L

Explanation:

Use the dilution equation M1V1 = M2V2

M1 = 0.075 M

V1 = 200 L

M2 = 2.5 M

V2 = ?

Solve for V2 --> V2 = M1V1/M2

V2 = (0.075 M)(200 L) / (2.5 M) = 6.0 L

4 0

2 years ago

Why cant magnesium ions be detected in a flam test?

Dmitry [639]

When magnesium ion doesn't give any characteristics colour with the flame test as electronic transisitons do not give out visible light.

6 0

2 years ago

The bonds in the reactants of Figure 7-3 contained 372 kJ of chemical energy and the bonds in the products contained 350 kJ of c

satela [25.4K]

Answer: 22 kJ amount of energy is released in the following reaction.

Explanation: There are two types of reaction on the basis of amount of heat absorbed or released.

1. Endothermic reactions: These are the type of reactions in which reactants absorb heat to form the products. The energy of the reactants is less than the energy of the products.

2. Exothermic reactions: These are the type of reactions in which heat is released from the chemical reactions. The energy of the products is less than the reactants.

Sign convention for $\Delta H$ : This value is negative for exothermic reactions and positive for endothermic reactions.

For the given chemical reaction,

Energy of the products is less than the energy of the reactants, Hence, this reaction will be a type of exothermic reaction and energy will be released during this chemical change.

Amount of energy released = (350 - 372) kJ = -22kJ

Negative sign symbolizes the energy is being released. So, 22 kJ amount of energy is released in the following reaction.

6 0

2 years ago