The atomic number of magnesium is 12.Find the number of electrons , protons and neutrons?

What pattern do you observe in the coefficients of the hydrocarbon (CxHy) and water (H2O)? How do you explain this pattern?

balu736 [363]

The coefficients of the hydrocarbon and water is 61 and it is explained below.

Explanation:

We have to balance the chemical equation that describes the combustion of octane C₈H₁₈. The combustion of octane involves burning this hydrocarbon in the presence of excess oxygen,O 2. Because octane is a hydrocarbon, that is the compound that contains only carbon and hydrogen, the reaction will produce two products carbon dioxide CO 2 and water H 2 O.

The unbalanced chemical equation is

C₈H₁₈ + O₂ → CO₂ + H₂O

To balance this equation, we have 8 present on the reactant side, so multiply the carbon dioxide by 8 to get 8 atoms of carbon on the products side.

C₈H₁₈ + O₂ → 8 CO₂ + H₂O

Now, we have 18 on the reactant side and 2 on the products side, so multiply the water molecule by 9 to get

C₈H₁₈ + O₂ → 8 CO₂ + 9 H₂O

8 * 2 atoms O + 9 *1 atoms O = 25 atoms O

By adding fractional coefficient to O₂ we get

C₈H₁₈ + $\frac{25}{2}$ O₂ → 8 CO₂ + 9 H₂O

Multiply all the coefficients by 2 we get,

2C₈H₁₈ + ( $\frac{25}{2}$ * 2) O₂ → 8 * 2 CO₂ + 9* 2 H₂O

The balance equation is

2C₈H₁₈ + 25 O₂ → 16 CO₂ + 18 H₂O

Add the coefficients to get their sum

= 2 +25 + 16 +18 = 61

Thus, The coefficients of the hydrocarbon and water is 61

6 0

3 years ago

What characterizes a radioactive atom?

elena-s [515]

Answer:

It's C

Protons repel the neutrons.

Explanation:

An atom is unstable (radioactive) if these forces are unbalanced; if the nucleus has an excess of internal energy. The instability of an atom's nucleus may result from an excess of either neutrons or protons.

6 0

3 years ago

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Avoiding an accident when driving can depend on reaction time. That time, measured in seconds from the moment the driver see dan

crimeas [40]

Answer:

The answer is below

Explanation:

A normal model is represented as (μ, σ). Therefore for (1.5, 0.18), the mean (μ) = 1.5 and the standard deviation (σ) = 0.18

The z score shows by how many standard deviations the raw score is above or below the mean. It is given as:

$z=\frac{x-\mu}{\sigma}$

a) For x < 1.35 s

$z=\frac{x-\mu}{\sigma}\\\\z=\frac{1.35-1.5}{0.18}=-0.83$

From the normal distribution table, the percent of drivers have a reaction time less than 1.35 seconds = P(x < 1.35) = P(z < -0.83) = 0.2033 = 20.33%

b) For x > 1.9 s

$z=\frac{x-\mu}{\sigma}\\\\z=\frac{1.9-1.5}{0.18}=2.22$

From the normal distribution table, the percent of drivers have a reaction time greater than 1.9 seconds = P(x > 1.9) = P(z > 2.22) = 1 - P(z<2.22) = 1 - 0.9868 = 0.0132 = 1.32%

c) For x = 1.45

$z=\frac{x-\mu}{\sigma}\\\\z=\frac{1.45-1.5}{0.18}=-0.28$

For x = 1.75

$z=\frac{x-\mu}{\sigma}\\\\z=\frac{1.75-1.5}{0.18}=1.39$

From the normal distribution table, P(1.45 < x < 1.75) = P(-0.28 < z < 1.39) = P(z < 1.39) - P(z< - 0.28) = 0.9177 - 0.3897 = 0.528 = 52.8%

d) A percentage of 10% corresponds to a z score of -1.28

$z=\frac{x-\mu}{\sigma}\\\\-1.28=\frac{x-1.5}{0.18}\\\\x-1.5=-0.2034\\\\x=1.27$

e) P(z < z1) - P(z< -z1) = 60%

P(z < z1) - P(z< -z1) = 0.6

P(z < -z1) = 1 - P(z < z1)

P(z<z1) - (1 - P(z < z1)) = 0.6

2P(z<z1) - 1= 0.6

2P(z<z1) = 1.6

P(z<z1) = 0.8

From the z table, z1 = 0.85

$0.85=\frac{x-1.5}{0.18}and-0.85=\frac{x -1.5}{0.18} \\\\x=1.65 \ and\ x=1.35$

The reaction time between 1.35 and 1.65 seconds

8 0

3 years ago

Calculate the pH for each of the following cases in the titration of 25.0 mL of 0.150 M sodium hydroxide with 0.150 M HBr(aq). (

Taya2010 [7]

Answer:

a) pH = 13.176

b) pH = 13

c) pH = 12.574

d) pH = 7.0

e) pH = 1.46

f) pH = 1.21

Explanation:

HBr + NaOH ↔ NaBr + H2O

∴ equivalent point:

⇒ mol acid = mol base

⇒ (Va)*(0.150mol/L) = (0.025L)*(0.150mol/L)

⇒ Va = 0.025 L

a) before addition acid:

NaOH → Na+ + OH-

⇒ C NaOH = 0.150 M

⇒ [ OH- ] = 0.150 M

⇒ pOH = - Log ( 0.150 )

⇒ pOH = 0.824

⇒ pH = 14 - pOH

⇒ pH = 13.176

b) after addition 5mL HBr:

⇒ C NaOH = (( 0.025)*(0.150) - (0.005)*(0.150)) / (0.025 + 0.005) = 0.1 M

⇒ C HBr = (0.005)*(0.150) / ( 0.03 ) = 0.025 M

⇒ [ OH- ] = 0.1 M

⇒ pOH = 1

⇒ pH = 13

c) after addition 15mL HBr:

⇒ C NaOH = ((0.025)*(0.150) - (0.015)*(0.150 ))/(0.04) = 0.0375 M

⇒ C HBr = ((0.015)*(0.150))/(0.04) = 0.0563 M

⇒ [ OH- ] = 0.0375 M

⇒ pOH = 1.426

⇒ pH = 12.574

d) after addition 25mL HBr:

equivalent point:

⇒ [ OH- ] = [ H3O+ ]

⇒ Kw = 1 E-14 = [ H3O+ ] * [ OH- ] = [ H3O+ ]²

⇒ [ H3O+ ] = 1 E-7

⇒ pH = 7.0

d) after addition 40mL HBr:

⇒ C HBr = ((0.04)*(0.150) - (0.025)*(0.150)) / (0.04 + 0.025) = 0.035 M

⇒ [ H3O+ ] = 0.035 M

⇒ pH = 1.46

d) after addition 60mL HBr:

⇒ C HBr = ((0.06)*(0.150) - (0.025)*(0.150)) / (0.06+0.025) = 0.062 M

⇒ [ H3O+ ] = 0.062 M

⇒ pH = 1.21

8 0

4 years ago

Read 2 more answers

3. Round the number 10.4656 to the tenths place * 10 10.4 10.5 or 10.6

motikmotik

Answer: 10.5 hope this helps!

5 0

3 years ago

The atomic number of magnesium is 12.Find the number of electrons , protons and neutrons?​

The atomic number of magnesium is 12.Find the number of electrons , protons and neutrons?