All categories

2 years ago

The sun is bigger than the Moon, but they appear to be the same size in the sky when you look at them from Earth. Why?

Chemistry

1 answer:

pogonyaev2 years ago

8 0

Answer:

The moon is closer to Earth than the sun! (Last one)

Explanation:

You might be interested in

You are instructed to create 900. mL of a 0.29 M phosphate buffer with a pH of 7.8. You have phosphoric acid and the sodium salt

Aleksandr [31]

Answer:

B and C

Explanation:

When we have to do a buffer solution we always have to choose the reaction that has the pKa closer to the desired pH value. When we find the pKa values we will obtain:

$pKa_1=-Log[6.9x10^-^3]=2.16$

$pKa_2=-Log[6.2x10^-^8]=7.20$

$pKa_3=-Log[4.8x10^-^13]=12.31$

The closer value is pKa2 with a value of 7.2. Therefore we have to use the second reaction. In which $H_2PO_4^-^1$ is the acid and $HPO_4^-^2$ is the base. Therefore the answer for the first question is B and the answer for the second question is C.

8 0

2 years ago

Thre largest source of available freshwater on earth is

Burka [1]

Ice caps so it would be D

Hope it helps :-)

6 0

2 years ago

Read 2 more answers

Which planets mass is nearly double that of mercury?

Nana76 [90]

Answer:

earth I think like that because earth is the second planet

4 0

2 years ago

Determine the basic oxidation number for elements in s and p orbitals

Andrews [41]

Answer:

Explanation:

The oxidation state, sometimes referred to as oxidation number, describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. Conceptually, the oxidation state, which may be positive, negative or zero, is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic, with no covalent component. This is never exactly true for real bonds.

The term oxidation was first used by Antoine Lavoisier to signify reaction of a substance with oxygen. Much later, it was realized that the substance, upon being oxidized, loses electrons, and the meaning was extended to include other reactions in which electrons are lost, regardless of whether oxygen was involved.

Helped?

Brainliest?

7 0

2 years ago

What geometry does VSEPR predict for the central atom in NCl3

Archy [21]

Answer:

Tetrahedral electron geometry and trigonal pyramidal molecular geometry.

Explanation:

The Lewis structure is shown in Figure 1.

The central N atom has three bonding pairs and one lone pair, for four electron groups.

VSEPR theory predicts a tetrahedral electron geometry with bond angles of 109.5°.

We do not count the lone pair in determining the molecular shape.

The molecular geometry is trigonal pyramidal (see Figure 2).

5 0

2 years ago