which one of the following can be separated by physical means:
(a) element
(b) mixture
(c) compound
(d) radical

Answer:

Electrons arrangement change is almost constant down the group, hence nuclear charge is almost constant.

But the energy levels on which electrons are arranged increase down the group, hence shielding or screening effect increases.

Answer: 40cm^3

Explanation:

Since the The air today is approximately one-fifth oxygen, the approximate volume of oxygen in 200cm3 of air would be:

= 1/5 × 200

= 40cm

The answer is 40cm^3

Answer:

A

Explanation:

I looked up aromatic hydrocarbon and this one looks like a replica of benzene

Answer:

i think the answer is D)

but u should ask the another person too:)

The empirical formula : C₁₀H₂₀O

Given

Combustion of menthol

Required

The empirical formula

Solution

Mass of CO₂ produced : 0.449 g

mass C = 12/44 x 0.449 = 0.122

Mass water produced : 0.1840 g

Mass H = 2.1/18 x 0.1840 = 0.02

Mass O in menthol :

=mass sample - (mass C+mass H)

= 0.1595 - (0.122+0.02)

= 0.0175

Mol ratio C : H : O in sample :

= 0.122/12 : 0.02/1 : 0.0175/16

= 0.01 : 0.02 : 0.001

= 10 : 20 : 1

Answer:

6.94 x 10²⁴molecules

Explanation:

Given parameters:

Mass of water  = 207.45g

Unknown:

Number of molecules  = ?

Solution:

To solve this problem, we must understand:

      1 mole of a substance  contains 6.02 x 10²³ molecules

Now, first find the number of moles of water;

 Number of moles  = [tex]\frac{mass}{molar mass}[/tex]  

 Molar mass of water  = 2(1) + 16  = 18g/mol

  Number of moles  = [tex]\frac{207.45}{18}[/tex]   = 11.53moles

So;

          1 mole of a substance  contains 6.02 x 10²³ molecules

       11.53moles of carbon dioxide will contain 11.53 x  6.02 x 10²³

                                                                 = 6.94 x 10²⁴molecules

Determine how many mL of solution A (acetic acid-indicator solution) must be added to solution B (sodium acetate-indicator solution) to obtain a buffer solution that is equimolar in acetate and acetic acid. Solution A: 10.0 mL 3.0e-4M bromescol green

hoped I helped

Answer:

Your answer is going to be B. the burning of fossil fuels

Explanation:

This is because carbon monoxide is extremely toxic for us humans. An example of this could be pollution. Hope this helps! :)

Answer: i rlly dont know srry

Explanation:

Answer:

Hydra bud

Explanation:

this plant reproduces asexually

Answer:

[tex]\boxed {\boxed {\sf About \ 1.040 \ moles \ of \ nitrogen }}[/tex]

Explanation:

To convert from grams to moles, we must use the molar mass. This can be found on the Periodic Table. We have a sample of nitrogen, so look for N on the table.

Now, use this molar mass as a ratio.

[tex]\frac {14.007 \ g \ N }{1 \ mol \ N }[/tex]

Multiply by the number of grams in the sample (14.57)

[tex]14.57 \ g \ N *\frac {14.007 \ g \ N }{1 \ mol \ N }[/tex]

Flip the fraction so the grams of nitrogen will cancel.

[tex]14.57 \ g \ N *\frac {1 \ mol \ N }{14.007 \ g \ N}[/tex]

[tex]14.57 *\frac {1 \ mol \ N }{14.007 }[/tex]

[tex]\frac {14.57 \ mol \ N }{14.007 }[/tex]

[tex]1.04019419 \ mol \ N \\[/tex]

The original measurement of grams had 4 significant figures, so we need to round our answer to the same number of sig figs.

For the number we calculated, that is the thousandth place. The 1 in the ten thousandth place tells us to keep the 0 in the thousandth place.

[tex]1.040 \ mol \ N[/tex]

There are about 1.040 moles of nitrogen in 14.57 grams.

Answer: The metal is Calcium.

Explanation:

To calculate the specific heat of substance during the reaction.

[tex]q=m\times c\times \Delta T[/tex]

where,

q = heat absorbed = 789.75 J

c = specific heat of metal = ?

m = mass of substance = 18.0 g

[tex]\Delta T_f[/tex] = final temperature  - initial temperature  = [tex](89.0-21.5)^0C=67.5^0C[/tex]

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

[tex]789.75J=18.0g\times c\times 67.5^0C[/tex]

[tex]c=0.65J/g^0C[/tex]

As specific heat is characteristic of each metal and thus the metal is calcium which has  specific heat of [tex]0.65J/g^0C[/tex]

Answer: amplitude, wavelength, and frequency.

Explanation:

Answer:

True

Explanation:

Answer:

False

Explanation:

Explanation:

1 mole is equal to 1 moles Iron(III) or 832.29538 grams, so 2 moles Iron(III) = 1664.59076 grams

Answer:

plankton

Explanation:

like in spongebob lol but for real I'm a marine biologist I know this is the answer lol

Answer:

I believe the answer is B. Noble gases.

Explanation:  

their outer shell is already full of electrons which makes then less reactive.

Answer: NaCl and H2O

Explanation: Products are on the right side of the arrow :)

Answer:

B. NaCI

D. H2O

Explanation:

The product is the result, which in this case is sodium chloride and water.

Answer:

cell,brain,tissue

Explanation:

answer; the last two is me and u :

The balanced equation

2Al(NO₃)₃ +  3FeCl₂ ⇒ 3Fe(NO₃)₂ + 2AlCl₃

Given

Reaction

Al(NO₃)₃ +  FeCl₂ --> Fe(NO₃)₂ + AlCl₃

Required

Balanced equation

Solution

Give a coefficient

aAl(NO₃)₃ +  bFeCl₂ --> Fe(NO₃)₂ + cAlCl₃

Make an equation

Fe, left=b, right=1⇒b=1

N, left=3a, right=2⇒3a=2⇒a=2/3

Cl, left=2b, right=3c⇒2b=3c⇒2.1=3c⇒c=2/3

The equation becomes :

2/3Al(NO₃)₃ +  FeCl₂ --> Fe(NO₃)₂ + 2/3AlCl₃ x3

2Al(NO₃)₃ +  3FeCl₂ --> 3Fe(NO₃)₂ + 2AlCl₃

Answer:

i thunk venus may be right or wrong tel7

Answer:

saturn:85 minutes

venus: 4.25 minutes

Explanation:

[tex] \frac{6.900 \times {10}^{10} }{4.000 \times {10}^{8} } \\ 1.725 \times {10}^{10 - 8} \\ 1.725 \times {10}^{2} [/tex]

Hope it will help you :)

Answer:

Explanation:

21:B 22:B

Answer:

1.05 hopefully this helps

Does anybody know what the dependent and independent variables are?

Answer:

C

Explanation:

LIFE LESSON: mixing cleaning products can create toxic chemicals and gas. please do NOT attempt doing anything like that kids.