Which one of the following statements is not true? a. Basalt magmas, in general, have higher temperatures than rhyolite magmas.
b. When magma reaches the surface, its dissolved gas content increases.
c. Melting temperatures of silicate rocks are lowered by small amounts of water.
d. Melting temperatures of silicate rocks increase with increased pressure.
Answers
Answer:
When magma reaches the surface, its dissolved gas content increases is true
Explanation:
The volcanic eruptions happen because of magma that is expelled on the earth’s surface. At the earth’s depth, all magma have gas dissolved in liquid. When the pressure has decreased the magma rises towards the earth’s surface creating a separate vapour phase.
As pressure reduces the volume of gas will expands and giving magma its 'explosive character'. Thus, as magma reaches the surface the dissolved gas content decreases and magma comes out of earth’s surface.
Final answer:
The untrue statement is b, as the dissolved gas content in magma decreases as it reaches the surface due to reduced pressure. Basalt magma has higher temperatures than rhyolite magma. Water reduces the melting temperature of silicate rocks, and increased pressure raises it.
Explanation:
The subject here pertains to volcanic activity and magma characteristics. The statement that is not true is: b. When magma reaches the surface, its dissolved gas content increases. In fact, as magma rises to the surface, the pressure decreases which allows the dissolved gases to escape, thus its dissolved gas content actually decreases. Statements a, c and d are true - Basalt magmas do generally have higher temperatures than rhyolite magmas. Additionally, the presence of water does indeed lower the melting temperature of silicate rocks, and increased pressure results in a higher melting temperature for these rocks.
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3.16 × 10−8
Explanation:
Answers
Half life of the given radioactive substance after 1000 years is 500 years.
What is half life?
Half -life of a substance is defined as the time which is required for half of the quantity of a radioactive substance to get decayed.It is a term which is used in nuclear chemistry for describing how quickly unstable atoms undergo radioactive decay into other nuclear species by emitting particles or the time which is required for number of disintegrations per second of radioactive material to decrease by one half of its initial value.
For the given problem, T=1000 years and N=25% of N°
where T=time period , N=amount of quantity after decay ,N°= initial quantity.
Here,N=25% of N°
N=25/100 N°=N°/4
N°/4=N°/2
n=2
∵nt=T
So. 2t=1000
t=500 years.
Hence, the half-life of a substance is 500 years.
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25% means that 2 half-lives have already passed. So one half-life is 500 years.
Answers
Answer:
summer solstice
Explanation:
on june solstice the northen hemisphere leans more toward the sun giving us longer days and more strong sunlight and It's the opposite in the Southern Hemisphere where june marks the start of winter thus its the shortest day of the year
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Answer:
70 peeecenr is thee answe
Answers
Answer:
Explanation:
The atomic number of zinc is 30, which means that the neutral atom has equal numbers of protons and electrons, so a neutral atom of zinc would have 30 electrons.
The electron configuration of a neutral zinc atom is 1s
2
2s
2
2p
6
3s
2
3p
6
3d
10
4s
2
.
The Zn
2+
ion has lost two electrons, which leaves it with 30 protons and 28 electrons.
The electron configuration of Zn
2+
is 1s
2
2s
2
2p
6
3s
2
3p
6
3d
10
.