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3 years ago

Which of the following statements is true about catalysts? and Why?

2 answers:

8 0

I believe the correct answer from the choices listed above is option D. Catalysts lower the activation energy of a chemical reaction. It is a substance which speeds up a reaction, but is chemically unchanged at the end of the reaction. It provides another pathway for the reaction to occur.

Strike441 [17]3 years ago

4 0

Your answer will be C. It's not D i just took the test

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A serving of Frosted Flakes cereal contains 235,000 J of energy. Calculate the change in temperature (ΔT) that would occur if th

timama [110]

The change in temperature (ΔT) : 56.14 ° C

<h3>Further explanation</h3>

Given

Cereal energy = 235,000 J

mass of water = 1000 g

Required

the change in temperature (ΔT)

Solution

Heat can be formulated :

Q = m . c . ΔT

c = specific heat for water = 4.186 J / gram ° C

235000 = 1000 . 4.186 . ΔT

$\tt \Delta T=\dfrac{235000}{1000\times 4.186}=56.14^oC$

3 0

2 years ago

Copper(II) sulfide is formed when copper and sulfur are heated together. In this reaction,

storchak [24]

Answer:

The mass of copper(II) sulfide formed is:

= 81.24 g

Explanation:

The Balanced chemical equation for this reaction is :

$Cu(s) + S\rightarrow CuS$

given mass= 54 g

Molar mass of Cu = 63.55 g/mol

$Moles = \frac{given\ mass}{Molar\ mass}$

$moles=\frac{54}{63.55}$

Moles of Cu = 0.8497 mol

Given mass = 42 g

Molar mass of S = 32.06 g/mol

$Moles = \frac{given\ mass}{Molar\ mass}$

$moles=\frac{42}{32.06}$

Moles of S = 1.31 mol

Limiting Reagent : The reagent which is present in less amount and consumed in a reaction

First find the limiting reagent :

$Cu + S\rightarrow CuS$

1 mol of Cu require = 1 mol of S

0.8497 mol of Cu should require = 1 x 0.8497 mol

= 0.8497 mol of S

S present in the reaction Medium = 1.31 mol

S Required = 0.8497 mol

S is present in excess and Cu is limiting reagent

All Cu is consumed in the reaction

Amount Cu will decide the amount of CuS formed

$Cu + S\rightarrow CuS$

1 mole of Cu gives = 1 mole of Copper sulfide

0.8497 mol of Cu = 1 x 0.8497 mole of Copper sulfide

= 0.8497

Molar mass of CuS = 95.611 g/mol

$Moles = \frac{given\ mass}{Molar\ mass}$

$0.8497 = \frac{given\ mass}{95.611}$

Mass of CuS = 0.8497 x 95.611

= 81.24 g

3 0

3 years ago

You have a two-liter sample of each of the following gases, all at 25 °C and one atmosphere pressure. Which sample will weigh th

stepladder [879]

Answer: D) Nitrogen Dioxide

Explanation:

4 0

2 years ago

How many moles of Fe are in 235.45g of Fe

Elena-2011 [213]

We are given with an element Iron, Fe, with a mass of 235.45 g. We are tasked to solve for its corresponding molar mass in mol. We need to find first the molecular weight of Iron, that is
Fe= 55.845 g/mol
With 235.45 g sample, its corresponding mol is

mol Fe= 235.45 g x 1 mol/55.845 = 4.22 mol Fe
Therefore, molar mass of Iron is 4.22 mol

3 0

2 years ago

The graph above shows the progress of a chemical reaction. Based on the graph, which of the following is true?

Helen [10]

I believe the answers b

6 0

3 years ago

Read 2 more answers