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3 years ago

Select the correct answer.

Chemistry

2 answers:

Fittoniya [83]3 years ago

8 0

Answer:

Explanation:

An ion has a net charge of 3+

ion has 8 protons

How many electrons does it have

A neutral atom has equal number of electrons and protons.

If a neutral atom loses electron it acquires a positive charge.

So to acquire 3+ charge the atom must have lost three electrons.

So the number of protons exceeds the number of electrons by 3.

Gwar [14]3 years ago

7 0

Answer is 5 tho idk why the options so weird. anyways u have to use the periodic table, check for the element which has 8 protons. this will be oxygen.

to calculate electrons, take 16-8 hence u will have 8 electrons.

qn said u have net charge of 3+. this means that u have to minus 3 from the electrons

so 8-3 = 5

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A sample of propane (C3H8) has a mass of 0. 47 g. The sample is burned in a bomb calorimeter that has a mass of 1. 350 kg and a

Nady [450]

The amount of heat released by the sample has been 22.54 kJ. Thus, option C is correct.

The specific heat has been defined as the amount of heat required to raise the temperature of 1 gram of substance by 1 degree Celsius.

The specific heat has been expressed as:

$q=mc\Delta T$

<h3 /><h3>Computation for the heat absorbed</h3>

The iron and calorimeter are in side the closed system. Thus, the energy released by the sample, has been equivalent to the energy absorbed by the calorimeter.

$q_{released}=q_{absorbed}\\
q_{released}=m_{calorimeter}\;c_{calorimeter}\;\Delta T$

The given mass of calorimeter has been, $m_{calorimeter}=1350\;\rm g$

The specific heat of the calorimeter has been, $c_{calorimeter}=5.82\;\rm J/g^\circ C$

The change in temperature of the calorimeter has been, $\Delta T=2.87^\circ \rm C$

Substituting the values for heat released:

$q_{released}= 1350\;\text g\;\times\;5.82\;\text J/\text g^\circ \text C\;\times\;2.87^\circ \text C\\
q_{released}=22,549.5\;\text J\\
q_{released}}=22.54\;\rm kJ$

The amount of heat released by the sample has been 22.54 kJ. Thus, option C is correct.

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2 years ago

three molecules of oxygen react with four molecules of hydrogen to produce water molecules write a balanced chemical equation

mixer [17]

Answer:

ExpC

→

This is the balanced reaction equation for the combustion of methane.

Explanation:

The Law of Conservation of Mass basically states that matter can neither be created nor destroyed. As such, we must be able to show this in our chemical reaction equations.

If you look at the equation above, you'll see an arrow that separates the reaction equation into two parts. This represents the direction of the reaction.

To the left of the arrow, we have our reactants.

To the right of the arrow, we have our products.

The quantity of each individual element in the left must equal the quantity of each individual element in the right.

So if you look below, you'll see the unbalanced equation, and I'll try to explain how to balance the reaction.

→

Our reactants in this equation are

and

Our next step is to break these down into individual atoms.

We have:

1 C atom, 4 H atoms & 2 O atoms.

If you're confused by this, look to see the little number to the bottom right of each element, the subscript, and it tells you how many of each atom are in the molecule. Make sense?

Now we look to the other side of the equation.

Here we see our products are

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2 years ago

The ____ can be described as the basic unit of life. (2 points) atom neutron cell nucleus

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2 years ago

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When a bond between a hydrogen atom and a sulfur atom is formed, electrons are?

nekit [7.7K]

They become an ionic bond, and are weakly bonded compared to covalently bonded atoms

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2 years ago

the specific heat capacity of water is 1 cal/gc how much heat in calories is released when 25.7 of water is cooled from 85 to 49

liraira [26]

Answer:

The amount of heat that is released is -925.2 cal

Explanation:

Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.

Sensible heat is the amount of heat that a body can receive or release without affecting its molecular structure, that is, it does not change the state (solid, liquid, gaseous). In other words, sensible heat is the amount of heat that a body absorbs or releases without any changes in its physical state.

The equation that allows to calculate heat exchanges is:

Q = c * m * ΔT

Where Q is the heat exchanged by a body of mass m, constituted by a substance of specific heat c and where ΔT is the variation in temperature.

In this case:

c= 1 $\frac{cal}{g*C}$
m= 25.7 g
ΔT= Tfinal - Tinitial= 49 °C - 85 °C= -36 °C

Replacing:

Q= 1 $\frac{cal}{g*C}$ *25.7 g* (-36 C)

Solving:

Q= -925.2 cal

<u><em>The amount of heat that is released is -925.2 cal</em></u>

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