(03.03 MC)

Explain what happens to the heat that is being added to a substance when the substance is changing phase.

nekit [7.7K]

When a substance changes from one state, or phase, of matter to another we say that it has undergone a change of state, or we say that it has undergone a change of phase. For example, ice melts and becomes water; water evaporates and becomes water vapor.These changes of phase always occur with a change of heat. Heat, which is energy, either comes into the material during a change of phase or heat comes out of the material during this change. However, although the heat content of the material changes, the temperature does not.

4 0

3 years ago

How does insect damage to crops in Kenya compare to insect damage to crops in North America

Dahasolnce [82]

Hello

Both America and Kenya have a high level of possible crop damage by insects. America is able to afford insecticides and the research to go with it, to control the pests. In Kenya farmers rotate their crops as much as possible (not always possible) and this helps in reducing the risk of pests. Also Kenyan farmers often grow rice in adjacent fields with sweet potatoes; this has reduced the weevil infestation level in sweet potatoes. The same technique can be used using sweet potato, intercropped with millet and sesame.

Have a nice day

8 0

3 years ago

5.80 gg of NaCl in 350. mL of a NaClsolution

Delicious77 [7]

Answer:

Solution is 0.28 M

You can also say, [NaCl] = 0.28 mol/L

Explanation:

As you have a solute mass and the solution's volume, you may find the molarity concentration of solution.

Molarity specifies the moles of solute in 1 L of solution

We convert the volume of solution to L → 350 mL . 1L / 1000 mL = 0.350L

We convert the mass of solute to moles → 5.80 g . 1mol / 58.45 g = 0.0992 moles

Molarity (mol/L) = 0.0992 mol /0.350L = 0.28M

6 0

3 years ago

A metal hammer has been lying in the sunlight on a hot day. When you pick up the hammer, it feels very warm in your hand. Can yo

tangare [24]

Answer:

When the hammer is in the sun, heat flows by radiation

When you pick up the hammer, heat flows by conduction

Explanation:

As the hammer lies in the sun, heat is transferred to the hammer by radiation. Heat energy reaches the earth from the sun by radiation. Radiation is a mode of beat transfer in which heat is transferred without a material medium.

When you pick up the hammer, heat flows to your hand by conduction because your body is a conductor of heat.

3 0

3 years ago

Please help me like now please

777dan777 [17]

Answer:

1-1) NaHCO3 + CH3COOH --> NaCH3COO + H2O + CO2

1-2) 0.5 mole of CO2

2-1) 2C4H10 + 13O2 --> 8CO2 + 10H2O

2-2) 4 mol CO2

Explanation:

Question 1

NaHCO3 + CH3COOH --> NaCH3COO + H2O + CO2

To balance the equation, count the number of atoms on both sides of the equation

(1 Na, 1+3+1H, 1+1+1C, 3+2Oxygen) --> (1 Na, 1+1+1C, 3+2H, 2+1+2Oxygen)

Combining the pluses will give you the following

(1 Na, 5H, 3C, 5Oxygen) --> (1 Na, 3C, 5H, 5Oxygen)

Both sides are the same, therefore the chemical equation is balanced (originally).

From the equation, we can see that 1 mole of NaHCO3 produces 1 mole of CO2.

So that means 0.5 mole of NaHCO3 would produce 0.5 mole of CO2.

Question 2

C4H10 + O2 --> CO2 + H2O

Again, count the number of atoms on both sides of the equation

(4C, 10H, 2O) --> (1C, 2H, 3O) This time left does not equal right side

You now need to find factors that can make both sides equal.

C4H10 + O2 --> 4CO2 + H2O Now the C is balanced, let's recount 

(4C, 10H, 2Oxygen) --> (4C, 8+1Oxygen, 2H) H&O is still not balanced

C4H10 + O2 --> 4CO2 + 5H2O Now the H is balanced, let's recount

(4C, 10H, 2Oxygen) --> (4C, 8+5Oxygen, 10H) O is still not balanced

C4H10 + (13/2)O2 --> 4CO2 + 5H2O Now the O is balanced

(4C, 10H, 13Oxygen) --> (4C, 13Oxygen, 10H)

But because 13/2 is a fraction, we want to eliminate that by multiplying every reactant and product by 2 (the denominator).

2C4H10 + 13O2 --> 8CO2 + 10H2O Now it's completely balanced!

(8C, 20H, 28Oxygen) --> (8C, 28Oxygen, 20H) Yayy! It's balanced.

Now, 2 mol C4H10 produces 8 mol CO2.

So 1 mol C4H10 produces 4 mol CO2.

6 0

2 years ago