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3 years ago

Write a balanced chemical equation for the reaction that occurs when heptane, C7H16(l) , burns in air.

1 answer:

8 0

Start with Unbalanced Equation and balance it, so...
C7H16+O2--->CO2+H2O
There are 7 C atoms on the left-hand side, so we need 7 C atoms on the right-hand side. Add a 7 in front of the CO2...7CO2+H2O on right side now.
We have fixed 16 H atoms on the left-hand side, so we need 16 H atoms on the right-hand side. Add an 8 in front of H2O to make 16 (8x2)...7CO2+8H2O on right side now.
There are 22 O atoms on the right-hand side: 14 from the CO2 and 8 from the H2O. Add an 11 in front of the O2 on the left side to make 22 (11x2).
Every formula now has a fixed coefficient. You should have a balanced equation of...
C7H16+11O2--->7CO2+8H2O

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Do substances react by mass? Yes or no explain

daser333 [38]

yes substances Do react by mass

5 0

3 years ago

What is the wavelength if the frequency is 29.2 hz?

ZanzabumX [31]

Answer : The wavelength is $1.027\times 10^7m$

Solution : Given,

frequency = 29.2 Hz

Formula used :

$\nu=\frac{c}{\lambda}\\\lambda=\frac{c}{\nu}$

where,

$\nu$ = frequency

$\lambda$ = wavelength

c = speed of light = $3\times 10^8m/s$

Now put all the given values in this formula, we get the wavelength.

$\lambda=\frac{3\times 10^8m/s}{29.2Hz}=0.1027\times 10^8m=1.027\times 10^7m$ $(1Hz=1s^{-1})$

Therefore, the wavelength is $1.027\times 10^7m$

8 0

3 years ago

If 8.00 g NH4NO3 is dissolved in 1000 g of water, the water decreases in temperature from 21.00 degrees Celsius to 20.39 degrees

telo118 [61]

Answer:

25.7 kJ/mol

Explanation:

There are two heats involved.

heat of solution of NH₄NO₃ + heat from water = 0

q₁ + q₂ = 0

n = moles of NH₄NO₃ = 8.00 g NH₄NO₃ × 1 mol NH₄NO₃/80.0 g NH₄NO₃

∴ n = 0.100 mol NH₄NO₃

q₁ = n * ΔHsoln = 0.100 mol * ΔHsoln

m = mass of solution = 1000.0 g + 8.00 g = 1008.0 g

q₂ = mcΔT = 58.0 g × 4.184 J°C⁻¹ g⁻¹ × ((20.39-21)°C) = -2570.19 J

q₁ + q₂ = 0.100 mol ×ΔHsoln – 2570.19 J = 0

ΔHsoln = +2570.19 J /0.100 mol = +25702 J/mol = +25.7 kJ/mol

7 0

3 years ago

The Pauli Exclusion Principle tells us that no two electrons in an atom can have the same four quantum numbers.

Anuta_ua [19.1K]

Answer:

See explanation

Explanation:

We can describe electrons using four sets of quantum numbers;

principal quantum number (n)

orbital quantum number (l)

magnetic quantum number (ml)

spin quantum number (ms)

Since no two electrons in an atom can have the same value for all four quantum numbers according to Pauli exclusion theory, for the orbitals given one possible value for each quantum number is shown below;

For 1s-

n = 1, l= 0, ml = 0, ms= 1/2

For 2s-

n= 2, l =0, ml=0, ms=1/2

For 1s and 2s orbitals, there is only one possible value for ml which is zero.

3 0

3 years ago

Mean, median and mode are best described as which?

Nonamiya [84]

Answer:

B. Measures of central tendency

Explanation:

Mean, median and mode are best described as measures of central tendency of a given data set.

Mean is the average of the samples given

Mode is the data point with the most frequent occurrence

Median is the data point that lies in the middle

All these parameters tells us how far a data point is from the middle or how close they are.

5 0

3 years ago