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3 years ago

What is the biggest source of vitamin D

Chemistry

2 answers:

Aleksandr [31]3 years ago

5 0

The biggest source of vitamin D is the sun.

Lena [83]3 years ago

5 0

In terms of food, fish (like tuna) is one of the biggest source of vitamin D. However, the sun provides the biggest source of vitamin D.

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What is in a microscope the enlarges things so our eye can see them?

Fittoniya [83]

Answer:lenses

Explanation:

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3 years ago

Fill in the coefficients that will balance the following reaction: a0NaCl + a1FeO → a2Na2O + a3FeCl2

Helen [10]

Answer:

2NaCl + FeO —-> 2Na2O + FeCl2

Explanation:

4 0

3 years ago

Which of the following numbers count as exact numbers and do not count when determining significant figures in a calculation? 1.

rewona [7]

Answer :

(1) Density do not count as exact number.

(2) Volume count as exact number.

(3) Length count as exact number.

(4) Speed do not count as exact number.

(5) Number count as exact number.

(6) Mass do not count as exact number.

Explanation :

Exact numbers : It is a defined or integer value which comes from counting numbers of objects.

They have an infinite number of significant figures.

For example : 12 eggs in a dozen, 1000 g in a kilogram and 2.54 cm in an inch.

Now we have to determine the following numbers count as exact numbers.

(1) Density : 3.7 g/mL

Density do not count as exact number.

(2) Volume : 1000 mL/L

Volume count as exact number.

(3) Length : 2.54 cm/in

Length count as exact number.

(4) Speed : 65.2 km/hr

Speed do not count as exact number.

(5) Number : 14 aardvarks

Number count as exact number.

(6) Mass : 38.741 g

Mass do not count as exact number.

4 0

3 years ago

Fill in the chart to describe and give examples of physical changes.

frosja888 [35]

Answer:

here are some examples of physical change!!!

Explanation:

-An ice cube melting into water in your drink.

-Freezing water to make ice cubes.

-Boiling water evaporating.

-Hot shower water turning to steam.

-Steam from the shower condensing on a mirror.

8 0

3 years ago

Read 2 more answers

Arrange the elements in decreasing order of first ionization energy.

just olya [345]

Answer:

The decreasing order of first ionization energy: Se > Ge > In > Cs

The decreasing order of first ionization energy: x > y > z

Explanation:

Ionization energy refers to the energy needed to completely pull out an electron from the valence shell of a neutral gaseous atom.

First ionization energy is the energy involved in the removal of first valence electron.

In the periodic table, down the group, as atomic radius of elements increases, the ionization energy decreases

Whereas, across a period, as atomic radius of elements decreases, the ionization energy increases.

PART (A):

Position of the given elements in the periodic table:

Indium (In): Group 13, period 5

Germanium (Ge): Group 14, period 4

Selenium (Se): Group 16, period 4

Caesium (Cs): Group 1, period 6

Thus, the increasing order of atomic radius: Se < Ge < In < Cs

Therefore, the decreasing order of first ionization energy: Se > Ge > In > Cs

PART (B):

Given elements:

element x: radius = 110 pm

element y: radius = 199 pm

element z: radius = 257 pm

Thus, the increasing order of atomic radius: x < y < z

Therefore, the decreasing order of first ionization energy: x > y > z

5 0

3 years ago