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3 years ago

Describe at least three ways our understanding of the atom has changed overtime?

Chemistry

1 answer:

myrzilka [38]3 years ago

7 0

Answer:

multitide of uses (drinking, cleaning, cooking, transportation). Without water we would not survive. -Lead atoms bond together and they make up the lead that we use as a pencil. -Copper atoms, aluminum atoms, nickel atoms, etc., all make up metal which is used for a variety of things in everyday life.

Explanation:

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How many liters of air must react with 2500 mL of hexane in order for combustion to occur completely. The percentage of oxygen i

bagirrra123 [75]

Answer:

118750 ml

Explanation:

The chemical equation for complete combustion of hexane is given as;

2C6H14 + 19O2 → 12CO2 + 14H2O

From the equation of the reaction;

2 mol of C6H14 reacts with 19 mol of O2

2 ml of C6H14 reacts with 19 ml of O2

2500 mL of C6H14 would react with x ml of O2

2 = 19

2500 = x

x = 2500 * 19 / 2 = 23750 ml

Since oxygen is 20% of air;

23750 = 20 / 100 * (Volume of air)

Volume of air = 23750 * 100 / 20 = 118750 ml

7 0

3 years ago

How much heat, in joules, must be added to a 75.0-g iron block with a specific heat of 0.449 J/g °C to increase its temperature

svp [43]

Answer:

50,849.25 Joules

Explanation:

The amount of heat, Q, required to raise the temperature of a body with mass, m, and specific heat capacity, c is given by:

Q = mcΔT, where ΔT represents the change in temperature.

In the case of the iron block:

m = 75 g

c = 0.449 J/g °C

ΔT = 1535 - 25 = 1510 °C

Therefore,

Q = 75 g x 0.449 J/g °C x 1510 °C

= 50,849.25 Joules

Hence, 50,849.25 Joules of heat must be added to a 75.0-g iron block with a specific heat of 0.449 J/g °C to increase its temperature from 25 °C to its melting temperature of 1535 °C

5 0

2 years ago

Be sure to answer all parts. Write the equations representing the following processes. In each case, be sure to indicate the phy

barxatty [35]

Answer:

1. $S^{-}(g)+e^{-} \rightarrow S^{2-}(g)$

2. $Ti^{2+}(g) \rightarrow Ti^{3+}(g) \,\, IE = 2652.5\,kJ.mol^{-1}$

3.The electron affinity of $Mg^{2+}$ is zero.

4. $O^{2-}(g) \rightarrow O^{-}(g)+e^{-}$

Explanation:

Electron affinity:

It is defined as the amount of energy change when an electron is added to atom in the gaseous phase.

The electron affinity of $S^{-}$ is as follows.

$S^{-}(g)+e^{-} \rightarrow S^{2-}(g)$

Ionization energy:

Amount of energy required to removal of an electron from an isolated gaseous atom.

The third ionization energy of Titanium is as follows.

$Ti^{2+}(g) \rightarrow Ti^{3+}(g) \,\, IE = 2652.5\,kJ.mol^{-1}$

The electronic configuration of Mg: $1s^{2}2s^{2}2p^{6}3s^{2}$

By the removal of two electrons from a magnesium element we get $Mg^{2+}$ ion.

$Mg^{2+}$ has inert gas configuration i.e, $1s^{2}2s^{2}2p^{6}$

Hence, it does not require more electrons to get stability.

Therefore,the electron affinity of $Mg^{2+}$ is zero.

The ionization energy of $O^{2-}$ is follows.

$O^{2-}(g) \rightarrow O^{-}(g)+e^{-}$

3 0

3 years ago

1. When this equation is balanced, Fe + 02 -.--> Fe203, what is the

Vilka [71]

Fe + O2 → Fe2O3

After balancing the eq.

4Fe + 3O2 → 2Fe2O3

Hope this will help u mate :)

4 0

3 years ago

when hydrogen atom absorbs a photon, and an electron moves level 1 to level 2, what happens to the energy of the atom?

pychu [463]

Answer:

When an electron is hit by a photon of light, it absorbs the quanta of energy the photon was carrying and moves to a higher energy state. One way of thinking about this higher energy state is to imagine that the electron is now moving faster, (it has just been "hit" by a rapidly moving photon).

Explanation: pls mark brainliest :))

7 0

2 years ago