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aalyn [17]
3 years ago
13

How does an exothermic change show that a chemical reaction occured?

Chemistry
1 answer:
Gre4nikov [31]3 years ago
8 0
With increasing temperature of the chemical reaction
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Having done the experiment, explain briefly how the mass of zinc not equal the mass of lead gained (hint: the periodic table)
masya89 [10]

Answer:

Due to the difference in the relative atomic masses and therefore, the molecular masses of Zn and Pb, one mole of Zn is about 3.2 times lighter than one mole of Pb

Explanation:

From the periodic table, we have;

The atomic number of zinc, Zn = 30

The atomic mass of zinc, Zn = 65.38 amu

The molar mass of zinc, Zn = 65.38 g/mol

The atomic number of lead, Pb = 82

The atomic mass of lead, Pb = 207.2 amu

The molar mass of lead, Pb = 207.2 g/mol

Therefore, whereby equal number of moles of Zn is lost and Pb is gained, we have;

Mass of 1 mole of Zn = 65.38 grams

Therefore, 1 gram of Zn = 1/65.38 moles = 0.0153 moles

0.12 grams of Zn = 0.12×0.0153 = 0.00184 moles of Zn

Given that equal number of moles of Zn and Pb are involved in the reaction, the number of moles of Pb gained = 0.00184 moles

The mass of Pb gained = Number of moles of Pb gained × Molar mass of Pb

The mass of Pb gained = 0.00184 × 207.2 = 0.38 g ≈ 0.4 g.

Amount of Pb gained = 0.43 g ≈ 0.4 g

4 0
3 years ago
What causes the Moon to revolve around Earth?
Mama L [17]

Answer:

A, Earth Gravity

Explanation:

7 0
2 years ago
Read 2 more answers
The term El Nino/Southern Oscillation refers to the occurrence of warmer than normal sea surface temperatures in the Eastern Pac
Amiraneli [1.4K]

Answer:

True

Explanation:

The  El Nino/Southern Oscillation occurs in between the three phases Neutral, La Nina or El Nino.

The humboldt current takes cold water to South America's west coast to the tropics from the  Southern Ocean. Because of the welling which takes place in Peru this process is enhanced. Due to the trade winds near the equator the cold water travels west where it heats up due to the sun. This makes the water of the western Pacific warmer.

6 0
3 years ago
Describe four effects that radiation can have on the human body.
Alinara [238K]

Answer:

There are many effects of radiation to the human body. (if you watch the 100, you'll see what happens)

Exposure to very high levels of radiation, such as being close to an atomic blast, can cause acute health effects such as

1. weakness

a/ fatigue,

b/ fainting,

c/ confusion.

2.Bleeding from the nose,

a/ mouth,

b/ gums,

c/ rectum

3. Bruising,

a/ skin burns,

b/ open sores on the skin,

c/ sloughing of skin.

4. Dehydration.

5. Diarrhea, bloody stool.

6. Fever.

7. Hair loss.

8. Inflammation of ex

5 0
3 years ago
What must happen in a chemical reaction?
klasskru [66]
The anwser is atoms are destroyed
6 0
3 years ago
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