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Marizza181 [45]
3 years ago
14

He distance from Earth to the North Star is about 430 light-years. Which of the following statements describes why scientists us

e the light-year unit to measure distances in space?
A light-year unit is very small and distances in space are very small.


A light-year unit is very small and distances in space are very large.


A light-year unit is very large and distances in space are very small.


A light-year unit is very large and distances in space are very large.
Chemistry
1 answer:
garri49 [273]3 years ago
8 0

Answer:

D

Explanation:

because the rest don’t make any sense

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Mitosis is an example of what
Phantasy [73]

Answer:

mitosis is Exampel of cell divison

Explanation:

mitosis is the second stage of cell divison or somatic cell divison

3 0
3 years ago
What are the first two quantum numbers for the electrons located in subshell 4d?
SCORPION-xisa [38]

Answer:

n = 4, l = 2

Explanation:

The number 4 in 4d is the principal quantum number (n).

The letter d in 4d tells us that we have a d orbital, as determined by the <em>secondary quantum number (l</em>).

The quantum number l tells us the shape of the orbital.

l = 0     s orbital

l = 1      p orbital

l = 2     d orbital

7 0
3 years ago
Read 2 more answers
The acid-dissociation constant for benzoic acid (C6H5COOH) is 6.3×10−5. Calculate the equilibrium concentration of H3O+ in the s
raketka [301]

Answer : The equilibrium concentration of H_3O^+ in the solution is, 2.1\times 10^{-3}M

Explanation :

The dissociation of acid reaction is:

                       C_6H_5COOH+H_2O\rightarrow H_3O^++C_6H_5COO^-

Initial conc.        c                                 0                0

At eqm.             c-x                                 x                x

Given:

c = 7.0\times 10^{-2}M

K_a=6.3\times 10^{-5}

The expression of dissociation constant of acid is:

K_a=\frac{[H_3O^+][C_6H_5COO^-]}{[C_6H_5COOH]}

K_a=\frac{(x)\times (x)}{(c-x)}

Now put all the given values in this expression, we get:

6.3\times 10^{-5}=\frac{(x)\times (x)}{[(7.0\times 10^{-2})-x]}

x=2.1\times 10^{-3}M

Thus, the equilibrium concentration of H_3O^+ in the solution is, 2.1\times 10^{-3}M

4 0
3 years ago
How many grams of CuF2 are needed to make a 2.8 M solution
11111nata11111 [884]
Molarity is given as,

                              Molarity  =  Moles / Volume of Solution  ----- (1)

Also, Moles is given as,

                              Moles  =  Mass / M.mass

Substituting value of moles in eq. 1,

                              Molarity  =  Mass / M.mass × Volume

Solving for Mass,

                              Mass  =  Molarity × M.mass × Volume  ---- (2)

Data Given;

                  Molarity  =  2.8 mol.L⁻¹

                  M.mass  =  101.5 g.mol⁻¹

                  Volume  =  1 L (I have assumed it because it is not given)

Putting values in eq. 2,

                              Mass  =  2.8 mol.L⁻¹ × 101.5 g.mol⁻¹ × 1 L

                              Mass  =  284.2 g of CuF₂
5 0
3 years ago
What does a straight line represent on a distance vs time graph?
stellarik [79]
A straight line on a distance va time graph represents constant speed
3 0
3 years ago
Read 2 more answers
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