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3 years ago

Describe one way in which advances in space technology have improved our understanding of objects in space.

Chemistry

1 answer:

Anika [276]3 years ago

7 0

Answer:

Technology helps us in many ways.

Explanation:

We can now research the world even more effectively and at a higher level of sophistication thanks to technological advancements. Telescopes, on the other hand, enable us to peer into the far corners of the universe and detect very large objects such as stars. Electron microscope enable us to see smaller objects such as cells and organisms.

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An alcohol is 68.84 % C and 4.962 % H by mass. The rest is oxygen. What is the empirical formula of the alcohol? Enter the eleme

Dafna1 [17]

The empirical formula is C₇H₆O₂.

Assume that you have 100 g of the compound.

Then you have 68.84 g C and 4.962 g H.

Mass of O = (100 – 68.84 – 4.962) g = 26.20 g O.

Now, we must convert these masses to moles and find their ratios.

From here on, I like to summarize the calculations in a table.

Element Mass/g Moles Ratio ×2 Integers

C 68.84 5.732 3.501 7.001 7

H 4.962 4.923 3.006 6.012 6

O 26.20 1.638 1 2 2

The empirical formula is C₇H₆O₂.

8 0

3 years ago

Describe the number of signals and their splitting in the 1H NMR spectrum of (CH3)2CHOCH3.

yanalaym [24]

Answer:

d. 3 signals: a singlet, a doublet, and a septet

Explanation:

In this case, we can start with the structure of $(CH_3)_2CHOCH_3$ . When we draw the molecule we will obtain 2-methoxypropane (see figure 1).

In 2-methoxypropane we will have three signals. The signal for the $CH_3$ groups in the left, the $CH$ and the $CH_3$ in the right. Lets analyse each one:

-) $CH_3$ in the right

In this carbon, we dont have any hydrogen as neighbors. Therfore we will have singlet signal in this carbon.

-) $CH$

In this case, we have 6 hydrogen neighbors ( the two methyl groups in the left). So, if we follow the n + 1 rule (where n is the amount of hydrogen neighbors):

$multiplicity~=~n+1~=~6~+~1~=~7$

For this carbon we will have a septet.

-) $CH_3$ in the left

In this case we have only 1 hydrogen neighbor (the hydrogen in $CH$ ). So, if we use the n+1 rule we will have:

$multiplicity~=~n+1~=~1~+~1~=~2$

We will have a doublet

With all this in mind the answer would be:

d. 3 signals: a singlet, a doublet, and a septet 

See figure 2 to further explanations

4 0

3 years ago

Hydrogen reacts with 0.771 g of carbon to form 0.90 g of a compound. What is the mass percent of hydrogen in the compound

morpeh [17]

Answer: 14.3%

Explanation: In order to find the mass percent of hydrogen in this compound, you must determine how many grams of hydrogen you'd get in 100 g of compound.

In your case, you know that an unknown mass of hydrogen reacts with 0.771 g of carbon to form 0.90 g of hydrocarbon, which is a compound that contains only carbon and hydrogen.

Use the total mass of the hydrocarbon to determine how many grams of hydrogen reacted with the carbon.

Now, if 0.90 g of this compound contain 0.129 g of hydrogen, it follows that 100 g of this compound will contain.

So, if 100 g of this compound contain 14.33 g of hydrogen, it follows that the mass percent of hydrogen is 14.3%

4 0

3 years ago

Read 2 more answers

In a 1.0x10^-4 M solution of HClO(aq), identify the relative molar amounts of these species:HClO, OH-, H3O+, OCl-, H2O

yarga [219]

HClO is a weak acid, which means the ions do not fully dissociate. The hydrolysis reaction for the hypochlorous acid is:

HClO + H2O ⇄ H3O+ +OCl-

Then the equilibrium constant, Ka, of dilute HClO would be:

$K_{a} = \frac{[ H_{3} O^{+} ][O Cl^{-} ]}{HClO}$

Then we do the ICE table. I is for the initial concentration, C for the change and E for the excess.

HClO + H2O ⇄ H3O+ + OCl-
I 1.0x10^-4 0 0
C -x +x +x
E (1.0x10^-4 - x) x x

Substituting the excess (E) concentration to the Ka equation:

$K_{a} = \frac{[x ][x]}{1.0 \ x \ 10^{-4} - x }$

Simplifying the equation would yield a quadratic equation:

$x^{2} + K_{a}x-(1.0 \ x \ 10^{-4}) K_{a}=0$

The Ka for HClO is an experimental data which was determined to be 2.9 x 10^-8. Substitute this to the equation, determine the roots, then you get the value for x, which is the concentration of H3O+ and ClO-. Just use your calculator feature Shift-Solve.

x = 1.688 x 10^-6 M = [H3O+] = [ClO-]

Then, you can determine the conc of [OH-] through pH.

pH = -log {H3O+] = -log [1.688 x 10^-6] = 5.77
pOH = 14 - pH = 14 - 5.77 = 8.23
pOH = 8.23 = -log [OH-]
[OH-] = 5.89 x 10^-9 M

Also, since HClO is (1.0x10^-4 - x), then it's concentration would be:
[HClO] = 1.0x10^-4 - 1.688 x 10^-6 = 9.83 x10^-5 M

Let's summarize all concentrations:
[HClO] = 9.83 x10^-5 M
[OH-] = 5.89 x 10^-9 M
[H3O+] = [ClO-] = 1.688 x 10^-6 M
Since the solution is dilute, H2O is relatively higher in concentration.

Thus in relative amounts, the order would be

H2O >>> HClO > H3O+ = ClO- > OH-

6 0

3 years ago

Read 2 more answers

Which element has a gas notation of [Kr]5s2 4d7

Olenka [21]

I think it would be Kriptonite

7 0

3 years ago