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3 years ago

Which of the following questions can be answered by science?

Chemistry

2 answers:

Irina18 [472]3 years ago

7 0

Answer:

A. What is the composition of air?, B. Should the driving age be reduced?, D.

Should students be allowed to bring toys to school? Answer: A,B,D.

Hunter-Best [27]3 years ago

6 0

Answer:

<h2>(a), (b) and (c) I guess</h2>

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What’s a predator? Are predators animals?

Setler [38]

Answer:

its an animal that preys on others

Explanation:

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3 years ago

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Determine the chemical formulas for the two compounds below. (Carbon, Hydrogen, and Oxygen).

tester [92]

Remember that any intersection of lines is a C, and that the number of hydrogens attached are the necessary to complet the 4 bonds.

1) CH3 - CH (OH) - CH (CH3) -CH3

2) CH3 - O - CH(CH3)-CH2 - CH3

I have used the parenthesis to indicate that the radical inside is in other branch, bonded by a single line -

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3 years ago

you see a coin at the bottom of a fountain of water but when you reach for it it is in another place than it appears to be

Roman55 [17]

Objects in the fountain appear to be somewhere but isnt

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3 years ago

2 points

erica [24]

9 grams of hydrogen gas (H2) will SC Johnson need to react in order to make 1 bottle of Windex.

Explanation:

Balance equation for the formation of ammonia from H2 gas.

N2 + 3H2 ⇒ 2 $NH_{3}$

Given

mass of ammonia in 1 bottle of windex = 51 gram

atomic mass of ammonia 17.01 gram/mole

number of moles = $\frac{mass}{atomic mass of 1 mole}$

number of moles = $\frac{51}{17.01}$

= 3 moles of ammonia is formed.

in 1 bottle of windex there are 3 moles of ammonia 0r 51 grams of ammonia.

From the equation it can be found that:

3 moles of hydrogen reacted to form 2 moles of ammonia

so, x moles of hydrogen will react to form 3 moles of ammonia.

$\frac{2}{3}$ = $\frac{3}{x}$

x = 4.5 moles of hydrogen will be required.

to convert moles into gram formula used:

mass = atomic mass x number of moles (atomic mass of H2 is 2grams/mole)

= 2 x 4.5

= 9 grams of hydrogen.

7 0

3 years ago

How much energy must be removed from a 94.4 g sample of benzene (molar mass= 78.11 g/mol) at 322.0 K to solidify the sample and

Kay [80]

Answer : The energy removed must be, 29.4 kJ

Explanation :

The process involved in this problem are :

$(1):C_6H_6(l)(322K)\rightarrow C_6H_6(l)(279K)\\\\(2):C_6H_6(l)(279K)\rightarrow C_6H_6(s)(279K)\\\\(3):C_6H_6(s)(279K)\rightarrow C_6H_6(s)(205K)$

The expression used will be:

$Q=[m\times c_{p,l}\times (T_{final}-T_{initial})]+[m\times \Delta H_{fusion}]+[m\times c_{p,s}\times (T_{final}-T_{initial})]$

where,

$Q$ = heat released for the reaction = ?

m = mass of benzene = 94.4 g

$c_{p,s}$ = specific heat of solid benzene = $1.51J/g^oC=1.51J/g.K$

$c_{p,l}$ = specific heat of liquid benzene = $1.73J/g^oC=1.73J/g.K$

$\Delta H_{fusion}$ = enthalpy change for fusion = $-9.8kJ/mol=-\frac{9.8\times 1000J/mol}{78g/mol}=-125.6J/g$

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

$Q=[94.4g\times 1.73J/g.K\times (279-322)K]+[94.4g\times -125.6J/g]+[94.4g\times 1.51J/g.K\times (205-279)K]$

$Q=-29427.312J=-29.4kJ$

Negative sign indicates that the heat is removed from the system.

Therefore, the energy removed must be, 29.4 kJ

3 0

3 years ago