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lilavasa [31]
3 years ago
6

All of the following are reasons why astronomers have difficulty looking at distant stars except:

Chemistry
1 answer:
OleMash [197]3 years ago
4 0

Answer:

B. They don't understand how red shift affects stars.

Explanation:

Astronomers face difficulty in observing distant stars because they are so far that they are easily viewed by telescope. Light pollution is major concern in present times . There is very less window present for observation. The dim light from the distance stars also gets distorted due to atmosphere and effects astronomical seeing.

Astronomers are aware about the Doppler effect for light that is the redshift effect on the star light. It is not a difficulty for astronomers.

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for a theoretical yield of 22 g and actual yield of 13 g, calculate the percent yield for a chemical reaction
sammy [17]

Answer:

59.09%

Explanation:

13/22*100=59.09%

8 0
3 years ago
There is 35 mg of sodium in a can of Coke. You determine it to be 28 mg. What is your percent error?
natali 33 [55]

Answer:

The answer is

<h2>20 %</h2>

Explanation:

The percentage error of a certain measurement can be found by using the formula

P(\%) =  \frac{error}{actual \:  \: number}  \times 100\% \\

From the question

actual volume = 35 mg

error = 35 - 28 = 7

The percentage error is

P(\%) =  \frac{7}{35}  \times 100 \\  =  \frac{1}{5}  \times 100 \\  =  20

We have the final answer as

<h3>20 %</h3>

Hope this helps you

8 0
3 years ago
Read 2 more answers
`Remember that an acid is something that donates hydrogen ions. So, when considering the formula HC2H3O2 (acetic acid), which of
tiny-mole [99]

Answer:

The H in the carboxyl group.

Explanation:

Acetic acid can be written as CH₃COOH, where -COOH is the functional group carboxyl, responsible for the acidity of organic acids. The H in the carboxyl group is the one that is donated in the acid reaction.

CH₃COOH(aq) + H₂O(l) ⇄ CH₃COO⁻(aq) + H₃O⁺

Acetic acid is a weak acid, so just a small fraction of the molecules undergo this reaction to donate their hydrogen.

5 0
3 years ago
Given these reactions, where X represents a generic metal or metalloid 1) H2(g)+12O2(g)⟶H2O(g)ΔH1=−241.8 kJ 1) H2(g)+12O2(g)⟶H2O
Bond [772]

Answer:

ΔH = -793,6 kJ

Explanation:

It is possible to obtain ΔH of this reaction using Hess's law that says you can sum the half-reactions ΔH to obtain the ΔH of the global reaction:

If half-reactions are:

1) H₂(g) + ¹/₂O₂(g) ⟶ H₂O(g) ΔH₁ = −241.8 kJ

2) X(s) + 2Cl₂(g) ⟶ XCl₄(s) ΔH₂ = +356.9 kJ  

3) ¹/₂H₂(g) + ¹/₂Cl₂(g) ⟶ HCl(g) ΔH₃ = −92.3 kJ

4) X(s) + O₂(g) ⟶ XO₂(s) ΔH₄ = −639.1 kJ

5) H₂O(g) ⟶ H₂O(l) ΔH₅ = −44.0 kJ

The sum of (4) + 4×(3) - (2) - 2×(1) - 2×(5) is:

(4) X(s) + O₂(g) ⟶ XO₂(s) ΔH = −639.1 kJ

+4×(3) 2H₂(g) + 2Cl₂(g) ⟶ 4HCl(g) ΔH = −369,2 kJ

-(2) XCl₄(s) ⟶ X(s) + 2Cl₂(g) ΔH = -356,9 kJ

-2×(1) 2H₂O(g) ⟶ 2H₂(g) + O₂(g) ΔH = +483,6 kJ

-2×(5) 2H₂O(l) ⟶ 2H₂O(g) ΔH = +88.0 kJ

= <em>XCl₄(s) + 2H₂O(l) ⟶ XO₂(s) + 4HCl(g)</em>

Where ΔH is:

ΔH = -639,1 kJ -369,2 kJ -356,9 kJ +483,6 kJ +88,0 kJ

<em>ΔH = -793,6 kJ</em>

I hope it helps!

5 0
3 years ago
How many atoms are in 34.2 grams of carbon?
Oksana_A [137]

Answer:

6.02*1022

Explanation:

I don't know why

8 0
3 years ago
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