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ella [17]
3 years ago
10

Grade 8 Science

Chemistry
1 answer:
Arada [10]3 years ago
4 0
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Methane burns in the presence of oxygen to form carbon dioxide and water.
wlad13 [49]

Answer:

= 9.28 g CO₂

Explanation:

First write a balanced equation:

CH₄ + 2O₂ -> 2H₂O + CO₂

Convert the information to moles

7.50g CH₄ = 0.46875 mol CH₄

13.5g O₂ = 0.421875 mol O₂

Theoretical molar ratio CH₄:O₂ -> 1:2

Actual ratio is  0.46875 : 0.421875 ≈ 1:1

If all CH₄ is used up, there would need to be more O₂

So O₂ is the limiting reactant and we use this in our equation

Use molar ratio to find moles of CO₂

0.421875 mol O₂ * 1 mol CO₂/2 mol O₂=0.2109375 mol CO₂

Then convert to grams

0.2109375 mol CO₂ = 9.28114 g CO₂

round to 3 sig figs

= 9.28 g CO₂

5 0
3 years ago
Complete the following table for the three key subatomic particles.
ASHA 777 [7]

Answer:

This question is incomplete without the table

Explanation:

The missing table is attached to this answer.

There are three subatomic particles found in an atom; protons, neutrons and electrons. The properties of the subatomic particles will be classified under the following subheadings (which are the empty columns/boxes in the attachment)

SYMBOL

The symbol of proton is "p⁺", the symbol of neutron is "n⁰" and the symbol of electron is "e⁻".

CHARGE

Looking at the symbol of the subatomic particles, one can guess the charge of each of the particles from the superscript.

Protons are positively charged, electrons are negatively charged while neutrons have no charge/electrically neutral.

The relative charge of proton is +1 while it's absolute charge is +1.60218 × 10⁻¹⁹

The charge of a proton was first determined by Ernest Rutherford using the gold-foil experiment

The relative charge of electron is -1 while it's absolute charge is -1.60218 × 10⁻¹⁹

The charge of an electron was first determined by R. Milikan using the oil-drop experiment

The relative charge and absolute charge of neutron is 0

The charge of a neutron was first determined by (or credited to) James Chadwick.

MASS

The relative mass (amu) of proton is 1.00727 while that of neutron is 1.00866. The relative mass (amu) of an electron is 0.00054858 while it's absolute mass (g) is 9.10939 × 10⁻²⁴.

The mass of an electron was first measured by J. J. Thomson.

The mass of a proton was first measured by (or credited to) Ernest Rutherford.

The mass of a neutron was first measured by James Chadwick.

LOCATION

The protons and neutrons <u>are located inside the nucleus</u> which is found in the centre of an atom while the electron(s)<u> is/are found outside the nucleus but within the atom</u>.

4 0
3 years ago
The process of __________ turns water vapor to liquid.
Elanso [62]
I belive this is called condensation.
hope this helps!
4 0
3 years ago
The pH of 0.10 M solution of an acid is 6. What is the acid dissociation constant of the acid?
svlad2 [7]

Answer: Dissociation constant of the acid is 10^{-11}.

Explanation: Assuming the acid to be monoprotic, the reaction follows:

                         HA\rightleftharpoons H^++A^-

pH of the solution = 6

and we know that

pH=-log([H^+])

[H^+]=antilog(-pH)

[H^+]=antilog(-6)=10^{-6}M

As HA ionizes into its ions in 1 : 1 ratio, hence

[H^+]=[A^-]=10^{-6}M

As the reaction proceeds, the concentration of acid decreases as it ionizes into its ions, hence the decreases concentration of acid at equilibrium will be:

[HA]=[HA]-[H^+]

[HA]=0.1M-10^{-6}M

[HA]=0.09999M

Dissociation Constant of acid, K_a is given as:

K_a=\frac{[A^-][H^+]}{HA}

Putting values of [H^+],[A^-]\text{ and }[HA] in the above equation, we get

K_a=\frac{(10^{-6}M).(10^{-6}M)}{0.09999M}

K_a=1.0001\times 10^{-11}M

Rounding it of to one significant figure, we get

K_a=1.0\times 10^{-11}M\approx 10^{-11}M

6 0
3 years ago
The first step in the scientific method usually is:
Alja [10]

Answer:

ask a question

Explanation:

You have to ask a question or solve a problem before you can develop a prediction/hypothesis, conduct an experiment or even make a conclusion. The question comes first.

5 0
3 years ago
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