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Natali [406]
3 years ago
15

Reactions are classified as either exothermic or endothermic. . ____________ reactions feel hot (e.g., a burning campfire), wher

eas _________reactions feel cool.
Chemistry
1 answer:
creativ13 [48]3 years ago
7 0

Answer:

Exothermic reactions feel hot

Endothermic reactions feel cool

Explanation:

In an exothermic reaction, heat is given out by the system. The energy of the reactants is greater than that of the products hence the excess energy is given off as heat. The reaction vessel feels hot.

In an endothermic reaction, the energy of products is greater than that of the reactants hence energy is taken into the system and the reaction vessel feels cool.

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an electric current causes water to be transformed into hydrogen and oxygen gasses a physical change or a chemical change
Natalija [7]
Physical change because ther is force which is the electric current
3 0
3 years ago
Homogenized milk is a colloid. It has been treated to prevent its different components from separating when it stands. When non-
frez [133]

Answer:

Heterogeneous mixture

Explanation:

A homogeneous mixture is defined as a mixture in which the constituents of the mixture are uniformly distributed. A typical example of a homogeneous mixture is when a salt is dissolved in water.

A heterogeneous mixture refers to a kind of mixture whereby the composition of the mixture is not uniform. A typically example of a heterogeneous mixture is non-homogenized milk.

Since non-homogenized milk is not homogeneous, the cream rises to the top and separates from the rest of the mixture because the emulsion has not been stabilized. However, homogenized milk is just milk whose emulsion has been stabilized the cream does not separate when left to stand.

7 0
3 years ago
What is the main source of energy in stars?
enot [183]

Answer:

nuclear fusion

4 0
4 years ago
Read 2 more answers
A rock sample from the moon includes a mineral that contains small amounts of the radioactive isotope Potassium-40 and its daugh
Simora [160]

Answer:

There were originally 8 atoms of Potassium-40.

Explanation:

The half-life of a radioactive material is the time taken for half the original material to decay or the time required for a quantity of the radioactive substance to reduce to half of its initial value.

If the original material formed without any Argon-40, it means that the atoms originally present were Potassium-40 atoms.

Presently, there are 7 Argon-40 atoms for every 1 of Potassium-40, we can deduce the number of half-lifes the Potassium-40 has undergone as follows :

After one half-life, (1/2) there will be one Potassium-40 atom for every Argon-40 atom.

After a second half life, 1/2 × 1/2 = 1/4: there will be one Potassium-40 atom for every three atoms of Argon-40.

After a third half-life, 1/4 × 1/2 = 1/8: there will be one Potassium-40 atom for every 7 atoms of Argon-40.

Since there are 1/8 atoms of Potassium-40 presently, there were originally 8 atoms of Potassium-40.

6 0
3 years ago
A solid has a volume of 64 cm3. Its mass is 288 g. What is its density?
lutik1710 [3]

Answer:

I think the answer is 4500 kilogram/cubic meter

6 0
4 years ago
Read 2 more answers
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