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4 years ago

What is the oxidation number of manganese (Mn) in potassium permanganate (KMnO4)? (3 points)

Chemistry

1 answer:

monitta4 years ago

7 0

K(+1)
Mn(x)
O(-2)
1+x-2*4=0
x=7

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When 2.00 g of methane are burned in a bomb calorimeter, the change in temperature is 3.08°C. The heat capacity of the calorimet

melisa1 [442]

Answer:

The approximate molar enthalpy of combustion of this substance is -66 kJ/mole.

Explanation:

First we have to calculate the heat gained by the calorimeter.

$q=c\times \Delta T$

where,

q = Heat gained = ?

c = Specific heat = $2.68 kJ/^oC$

ΔT = The change in temperature = 3.08°C

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

$q=2.68 kJ/^oC\times 3.08^oC$

$q=8.2544 kJ$

Now we have to calculate molar enthalpy of combustion of this substance :

$\Delta H_{comb}=-\frac{q}{n}$

where,

$\Delta H_{comb}$ = enthalpy change = ?

q = heat gained = 8.2544kJ

n = number of moles methane = $\frac{\text{Mass of methane}}{\text{Molar mass of methane }}=\frac{2.00 g}{16.042 g/mol}=0.1247 mole$

$\Delta H_{comb}=-\frac{8.2544 kJ}{0.1247 mole}=-66.21 kJ/mole\approx -66 kJ/mole$

Therefore, the approximate molar enthalpy of combustion of this substance is -66 kJ/mole.

6 0

3 years ago

The weak acid HA is 5 % ionized (dissociated) in a 0.35 M solution.

ddd [48]

Answer:idk

Explanation:of a 0.26 M triethylamine, (C2H5)3N, solution. ... 5. Predict if a decrease in temperature is favorable for the following reactions: (5 pts) a. H2O(s)

5 0

3 years ago

HELPPP<br> What do you think caused this land formation ?

Arturiano [62]

Answer:

Erosion/Weathering

Explanation:

Because the rock is exposed to the ocean, the constant push and pull of the water against the rock erodes the material away and moves it elsewhere. The wind likely aided in this process as well. This caused the big gap in the center of the rock.

6 0

3 years ago

Read the statements. In eukaryotic organisms, genes usually consist of two alleles. The two alleles are often on different parts

lina2011 [118]

Answer:

I think its B but im not too sure

5 0

2 years ago

If an object what is 30 kg of mass is moving at 10 m/s to the right how much kinetic energy does it have

ki77a [65]

Explanation:

m=30

v=10

K.E=1/2mv^2

=1/2×30×10^2

=1/2×30×100

=1500 joule

6 0

3 years ago