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3 years ago

3690 J of heat are added to a 21.5 g sample

Chemistry

1 answer:

Fiesta28 [93]3 years ago

6 0

Answer:

693K

Explanation:

The enthalpy change in the iron is 3690J

We now apply the formula for enthalpy change which is ΔH=mC∅ where ∅ is the temperature change, m the mass of the substance, and C the specific heat capacity for the substance.

ΔH in this case is 3690J.

Therefore 3690J=21.5g×0.449J/g.K×∅

as we are looking for ∅, we make it the subject of the formula.

∅=3690J/(21.5g×0.44J/g)

∅=390

Temperature=30°C +390

=420°+273

=693K

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What do these two changes have in common?

Varvara68 [4.7K]

ok fine ill leave

Explanation:

5 0

2 years ago

In an experiment, the molar mass of the compound was determined to

sasho [114]

Determine the mass in grams of each element in the sample. If you are given percent composition, you can directly convert the percentage of each element to grams.
For example, a molecule has a molecular weight of 180.18 g/mol. It is found to contain 40.00% carbon, 6.72% hydrogen and 53.28% oxygen.
Convert the percentages to grams.
40.00 grams of carbon
6.72 grams of hydrogen
53.28 grams of oxygen

3 0

3 years ago

Pure chlorobenzene (C6H5Cl) has a normal boiling point of 131.00 °C. A solution of 32.5 g of 2,8-dibromodibenzofuran (C12H6Br2O)

vichka [17]

Answer:

Kb → 1.56 °C / m

Explanation:

This is all about boiling point elevation, the colligative property that shows that boiling point for a solution is higher than boiling point of pure solvent.

This is the formula: ΔT = Kb . m . i

where i is the Van't Hoff factor (ions dissolved in solution). As these are organic compounds, we assume they are non electrolytic,

m is molality (mol of solute / 1kg of solvent)

Kb is our unknown. The value for ebulloscopic constant, it is specific for each solvent.

ΔT = T° boiling from solution - T° boiling from solute

First of all, let's determine the moles of solute.

Mass / Molar mass → 32.5 g/ 113.45 g/mol = 0.286 mol

Molality is mol of solute/ 1 kg of solvent

We must convert the mass from g to kg

195g . 1kg /1000 = 0.195 kg

Molality = 0.286 mol / 0.195 kg = 1.47 m

Let's replace the values in the formula

133.30 °C - 131°C = Kb . 1.47m .1

2.30°C / 1.47 m = Kb → 1.56 °C / m

3 0

3 years ago

Frederica is sitting on a moving train. She watches the telephone poles fly past. She knows that the poles in this area are 1/4

kupik [55]

B
1 mile=4 poles
if 5 poles pass by than she´s going around 1.25 miles per min
rounded up = 1.3 mil/min

8 0

3 years ago

The rate law for the reaction

juin [17]

Explanation:

Since, the given reaction is as follows.

$2NO(g) + Cl_{2}(g) \rightarrow 2NOCl(g)$

Hence, rate law of the reaction is as follows.

R = $k[NO][Cl_{2}]$

As it is known that rate of a reaction depends on the initial concentration of products. So here, the rate of reaction will depend on the concentration of NO and $Cl_{2}$ . Since, power of the concentrations of each of these is equal to 1. Therefore, order of the reaction is equal to 1 + 1 = 2.

According to the rate law, reactants involved in the rate determining step are NO and $Cl_{2}$ . Hence, first step of the mechanism is the rate determining step.

Also, according to the rate of reaction doubling the concentration of NO will double the rate of reaction.

The number of reactants taking part in a single step of the reaction is known as molecularity of the reaction. Therefore, molecularity of the first step of the reaction is 2.

Both the given steps are not termolecular.

5 0

4 years ago