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3 years ago

Compare and contrast reflecting and refracting telescopes. *

1 answer:

7 0

A refracting telescope uses convex lenses to gather a large amount of light and focus it onto a small area while a reflecting telescope the mirror instead of an objective lens they are also similar because like the lenses in a refracting telescope the mirror in a reflecting telescope focuses a large amount of light onto a small area.

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An atom's tendency is to become stable. What does this mean? A. The electrons all move to one electron shell. B. The atom gains

masya89 [10]

The answer is D. To put it simply, all atom wished to become stable. The only way for that is to obtain an octet structure where the outermost shell would have 8 electrons, thus being full.

3 0

4 years ago

Read 2 more answers

1) When 2.38g of magnesium is added to 25.0cm of 2.27 M hydrochloric acid, hydrogen gas is released.

Andrej [43]

Answer:

a. HCl.

b. 0.057 g.

c. 1.69 g.

d. 77 %.

Explanation:

Hello!

In this case, since the reaction between magnesium and hydrochloric acid is:

$Mg+2HCl\rightarrow MgCl_2+H_2$

Whereas there is 1:2 mole ratio between them.

a) Here, we can identify the limiting reactant as that yielded the fewest moles of hydrogen gas product via the 1:1 and 2:1 mole ratios:

$n_{H_2}^{by\ HCl}=0.025L*2.27\frac{molHCl}{1L}*\frac{1molH_2}{2molHCl} =0.0284molH_2\\\\n_{H_2}^{by\ Mg}=2.38gMg*\frac{1molMg}{24.3gMg}*\frac{1molH_2}{1molMg}=0.0979molH_2$

Thus, since hydrochloric yields fewer moles of hydrogen than magnesium, we realize it is the limiting reactant.

b) Here, we use the molar mass of gaseous hydrogen (2.02 g/mol) to compute the mass:

$m_{H_2}=0.0284molH_2*\frac{2.02gH_2}{1molH_2}=0.057gH_2$

c) Here, we compute the mass of magnesium associated with the yielded 0.0248 moles of hydrogen:

$m_{Mg}^{reacted}=0.0284molH_2*\frac{1molMg}{1molH_2}*\frac{24.3gMg}{1molMg} =0.690gMg$

Thus, the mass of excess magnesium turns out:

$m_{Mg}^{excess}=2.38g-0.690g=1.69gMg$

d) Finally, we compute the percent yield, considering 0.044 g is the actual yield and 0.057 g the theoretical yield:

$Y=\frac{0.044g}{0.057g} *100\%\\\\Y=77\%$

Best regards!

8 0

3 years ago

storchak [24]

"Electric charge: the proton and electron are electrically charged, while the neutron is not. The proton and electron, however, are oppositely charged. Role in the atom: Protons and neutrons are closely bound together in the nucleus of an atom, while electrons are spread out around the nucleus."

8 0

3 years ago

Which molecule below has hydrogen bonding? Which molecule below has hydrogen bonding? H2 CH3CH2OH HCl CH4 all of the above

QveST [7]

Answer:

$CH_3CH_2OH$

Explanation:

Hydrogen bonding:-

Hydrogen bonding is a special type of the dipole-dipole interaction and it occurs between hydrogen atom that is bonded to highly electronegative atom which is either fluorine, oxygen or nitrogen atom.

Partially positive end of the hydrogen atom is attracted to partially negative end of these atoms which is present in another molecule. It is strong force of attraction between the molecules.

Thus, hydrogen must be linked to electronegative atom which is oxygen, fluorine and nitrogen which is in $CH_3CH_2OH$ and thus, it will shown hydrogen bonding.

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3 years ago

Why is bronze preferred in making statue

cupoosta [38]

Bronze metal is harder and more malleable than copper. It is also conducts property of ductility, so it can be easily shaped as a statue.

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3 years ago