1125 J of energy is used to heat 250 g of iron to 55 °C. The specific heat capacity of iron is 0.45 J/(g·°C).

What was the temperature of the iron before it was heated?

55 °C
55 °C

35 °C
35 °C

45 °C
45 °C

20 °C

Answers

Answer 1

Answer:

45 °C.

Explanation:

From the question given above, the following data were obtained:

Heat (Q) = 1125 J

Mass (M) = 250 g

Final temperature (T₂) = 55 °C

Specific heat capacity (C) = 0.45 J/gºC

Initial temperature (T₁) =?

The initial temperature of the iron can be obtained as illustrated below:

Q = MC(T₂ – T₁)

1125 = 250 × 0.45 (55 – T₁)

1125 = 112.5 (55 – T₁)

Divide both side by 112.5

1125/112.5 = 55 – T₁

10 = 55 – T₁

Collect like terms

10 – 55 = –T₁

–45 = –T₁

Multiply through by –1

45 = T₁

T₁ = 45 °C

Therefore, the initial temperature of the iron is 45 °C


Related Questions

Hiii pls help me to write out the ionic equation ​

Answers

Answer:

STEP I

This is the balanced equation for the given reaction:-

[tex] 2KOH_{(aq)} + H_2SO_4{}_{(aq)} \rightarrow K_2SO_4{}_{(aq)} + 2H_2O_{(l)} [/tex]

STEP II

The compounds marked with (aq) are soluble ionic compounds. They must be

broken into their respective ions.

see, in the equation KOH, H2SO4, and K2SO4 are marked with (aq).

On breaking them into their respective ions :-

2KOH -> 2K+ + 2OH-H2SO4 -> 2H+ + (SO4)2-K2SO4 -> 2K+ + (SO4)2-

STEP III

Rewriting these in the form of equation

[tex] \underline{\pmb{2K^+} }+ 2OH^- + 2H^+ + \pmb{\underline{{SO_4{}^{2-}}} \: \rightarrow \: \underline{\pmb{2K^+}}} + \underline{\pmb{SO_4{}^{2-}}} + 2H_2O [/tex]

STEP IV

Canceling spectator ions, the ions that appear the same on either side of the equation

(note: in the above step the ions in bold have gotten canceled.)

[tex] \boxed{ \mathfrak{ \red{ 2OH^-{}_{(aq)} + 2H^+{(aq.)} \rightarrow H_2O{}_{(l)}}}} [/tex]

This is the net ionic equation.

____________________________

[tex] \\ [/tex]

[tex]\mathfrak{\underline{\green{ Why\: KOH \:has\: been\: taken\: as\: aqueous ?}}} [/tex]

KOH has been taken as aqueous because the question informs us that we have a solution of KOH. by solution it means that KOH has been dissolved in water before use.

[Alkali metal hydroxides are the only halides soluble in water ]

Which among the following mixtures will show tyndal effect?
i) copper sulphate solution
ii) sand in water.
iii) milk.
iv) starch solution ​

Answers

Answer:

milk and starch solution are the colloids, hence these will show the tyndall effect

Answer:

milk and starch solution

Explanation:

Tyndall effect is shown by colloidal solutions. It is not shown by true solutions or suspensions.

Milk and starch solution are colloidal solutions. They show tyndall effect. On the other hand, common salt and copper sulphate solution are true solutions. They do not show tyndall effect.

are standard electrode potential and standard hydrogen potential same?​

Answers

Answer:

Potentials of any other electrodes are compared with that of the standard hydrogen electrode at the same temperature. Hydrogen electrode is based on the redox half cell: 2 H+(aq) + 2 e− → H2(g)..

What is the pressure in atm exerted by 1.8 g of H2 gas exert in a 4.3 L balloon at 27ºC? R = 0.821(L*atm) / (mol*K)

Answers

kakamc cjdismxsjxj xjcodmd xksowmd x

The pressure in atm exerted by 1.8 g of H₂ gas exert in a 4.3 L balloon at 27ºC is 5.12 atm

What is Ideal gas law ?

The ideal gas law (PV = nRT) relates the macroscopic properties of ideal gases. An ideal gas is a gas in which the particles (a) do not attract or repel one another and (b) take up no space (have no volume).

Let's convert grams to moles (via molar mass).

Molar Mass (H₂) :  2 (1.008 g/mol)

Molar Mass (H₂) :  2.016 g/mol

1.8 grams H₂               1 mole

----------------------  x  ----------------------  =  0.893 moles H₂

                                2.016 grams

The Ideal Gas Law equation looks like this:

PV = nRT

In this equation,

P = pressure (atm) V = volume (L) n = moles R = Ideal Gas Constant (0.0821 L*atm/mol*K)T = temperature (K)

After converting Celsius to Kelvin, you can put the given values into the equation and simplify to find the pressure.

P = ? atm                                R = 0.0821 L*atm/mol*K

V = 4.3 L                               T = 27 °C + 273.15 = 300.15 K

n = 0.893 moles

PV = nRT

P (4.3 L) = (0.893 moles) (0.0821 L*atm/mol*K)( 300.15 K)

P (4.3 L) =  22.0021

P = 5.12 atm

Therefore, The pressure in atm exerted by 1.8 g of H₂ gas exert in a 4.3 L balloon at 27ºC is 5.12 atm

Learn more about Ideal gas here ;

https://brainly.com/question/8711877

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When it’s summer in the northern hemisphere what Season is it in the Southern Hemisphere

Answers

Answer:

Winter

Explanation:

I dont know but whatev

Answer:

Winter

Explanation:

The seasonal cycle in the polar and temperate zones of one hemisphere is opposite to that of the other. Therefore, When it is summer in the Northern Hemisphere, it is winter in the Southern, and vice versa.

hope it helps :)

Please help with the Volume one

Answers

Answer:

im a just achild

Explanation:

Answer:

c

Explanation:

0.5dm³

follow me if you want

Cho các dung dịch: Glucozơ, glixerol, fomanđehit, etanol. Có thể dùng thuốc thử nào sau đây để phân biệt được cả 4 dung dịch trên?

A. Cu(OH)2; B. Dung dịch AgNO3 trong NH3;

C. Na kim loại; D. Nước brom.



Xem thêm tại: https://loigiaihay.com/bai-2-trang-25-sgk-hoa-hoc-12-c55a8069.html#ixzz71KH6guhm

Answers

Answer:

chắc là câu B í

Explanation:

write any two conditions at which a body of certain mass weightless​

Answers

Answer:

A body becomes weightless in a zero-gravity scenario and when a force is applied to a body that is equal and opposite to the force of gravity. If the body is falling only under the influence of gravity.

Answer:

A body becomes weightless in a zero-gravity scenario and when a force is applied to a body that is equal and opposite to the force of gravity.If the body is falling only under the influence of gravity.

Can you help me on this. I will support your correct answer​

Answers

Iron+ nitric acid = Ferrous nitrate
Zinc+ sulphuric acid= Zinc sulphate

Magnesium chloride, Magnesium nitrate, magnesium sulphate

Please mark brainliest

Describe weighted average

Answers

Answer:

Explained below

Explanation:

In simple average, we just add all the given data variables and divide it by the number of data given.

However, when it comes to weighted average, what we do is that we multiply each given variable by their weights and then divide the sum of that by the sum of the weights.

Thus, if the variables are denoted by x and their weights are denoted by y, then we have;

Weighted average = Σ(xy)/Σy

what is a cubic unit cell ?​

Answers

cubic unit cell is the smallest repeated unit which have all angles equal to 90 and all have edge lengths equal

It is the type of the Unit cell which is having all angles equal to 90 and all sides equal to each other

it's is a unit cell with cubic structure

Which of the following is the best definition of a physical property?
A. Tearing paper in half.
B. Something that can be observed or measured while changing the identity of the substance.
C. The ability of something to undergo a change or reaction.
D. Something that can be observed or measured without changing the identity of the substance.

Answers

Answer:

D.Something that can be observed or measured without changing the identity of the substance.

Using your answers from part C, complete the chemical formula of each compound. If the number of ions is 1, leave that
number out of the formula.
Drag each number to the correct location. Numbers may be used more than once

Answers

Answer:

1;1, 2;1, 3;1, 1;2, 1;1, 3;2, 1;3, 2;3, 1;1.

I hope this will help.

Answer:

This is what the answer looks like

Explanation:

How many atoms of hydrogen are there in 36 g of NH4?

Answers

Answer:

hope it helps you

Explanation:

please like and mark me brainlist

The formula mass of ammonia is 14 + 1 3 = 17. The number of moles in 36 g ammonia is 36/ 17 = 2.11mol. A mole is 6.02 10, so the number of hydrogen atoms in a 2.11 moles of ammonia is 2.11 *6.02*10^23 = 1.27 *10^24 atoms .


Hope it helps!

A sample of gas has a volume of 20 cm³.The pressure is changed to 90 kPa at constant temperature,while the volume increases to 75 cm³.What was the original pressure of the gas?​

Answers

Answer:

337.5kPa ~ 338kPa

Explanation:

Using the ideal gas law PV=nRT we have the following definitions from the problem:

V(initial) = 20cm³

P(initial) = ?kPa

V(final) = 75cm³

P(final) = 90kPa

Since we know that the number of moles of the sample did not change, nor did the temperature, nor does the ideal gas constant (R) we can rewrite this equation to state:

P(initial)V(initial) = nRT =P(final)V(final) ~  P(initial)V(initial) = P(final)V(final)

Rearranging this equation as we are solving for the initial pressure we find that:

P(initial) = (P(final)V(final))/V(initial)

P(initial) = ((90kPa)(75cm³))/20cm³

P(initial) = 337.5kPa ~ 338kPA

I need help with question 5

Answers

Answer:

B a spring being stretched

in order to decrease the freezing point of 500. g of water to 1.00° c how many grams of ethylene glycol (C2H602)must be added (KF=1.86°C kg solvent)

Answers

Answer:

if wrong sorry ok????

why water can reduce unpleasant smell that produce from methane gas ?

Answers

Answer:Water contains Oxygen the purified the methane gas

Explanation:

I’m going to assume because it dilutes the methane gas and its odor

True or false, The four units that must always be used when using the ideal gas are 44.0 liters

Answers

Answer:

for volume only liters can be used

Explanation:

What does the prefix trans-indicate?
A. There are at least two double bonds in the molecule.
B. The carbons on either side of the double bond are pointed in
opposite directions.
C. The molecule is an alkane with no double bonds.
O D. The carbons on either side of the double bond are pointed in the
same direction

Answers

Answer:

B. The carbons on either side of the double bond are Pointed in opposite directions

Plants in forests take up carbon dioxide from the atmosphere during photosynthesis. They transform the carbon dioxide into plant material. When plants die, their organic matter is often worked into the soil by decomposers. Some of this organic matter remains within the soil and forest floor, and some of it is taken up by other living things.

Based on this information, what role do forests play in the carbon cycle?
A.
Forests are carbon sinks because they store carbon.
B.
Forests are carbon sinks because they do not absorb carbon dioxide when plants die.
C.
Forests are carbon sources because they emit carbon.
D.
Forests are carbon sources because they can be burned to emit carbon dioxide.

Answers

Answer is A

Because Trees store carbon and make it oxygen

Answer: B. forests are carbon sinks because they store carbon

Explanation:forests take up carbon from the atmosphere through photosynthesis and from organic matter through decomposition. so, forests are carbon sinks because they store carbon

Is FeS iron (ll) sulfide or iron (lll) sulfide?

Answers

Answer:

the valence of S is -2. For FeS to be neutral the valence of Fe used must be +2

and since Iron (II) has its valency 2, FeS will be Iron (II) Sulfide.

Which of the following molecules contains six bonding electrons?
A C2H4
B CO2
C H2S
D NCl3

Answers

Answer:

c2h4 (etthane........

bexcuse it has 6 bond of hydrogen

C₂H₄ molecules contains six bonding electrons. Therefore, option A is correct.

What do you mean by the term bonding ?

Chemical bonding is the process through which two or more atoms, molecules, or ions establish a chemical link to create a chemical compound. The atoms in the resultant molecule are held together by these chemical bonds.

Chemical bonds have three basic characteristics that must be taken into account: their strength, length, and polarity. The distribution of electrical charge among the atoms connected by a bond determines its polarity.

C₂H₄ molecules has six bonding electrons. This molecule is called as Ethylene. When bonding is done between two atoms, each atom shares a pair of electrons with each other.

Hence, for every one bond, two electrons are shared between two atoms

Thus, option A is correct.

To learn more about the bonding, follow the link;

https://brainly.com/question/10777799

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Which equation describes a physical change? i. H2O(s) ⟶ H2O(l) ii. Na+(aq)+Cl−(aq) +Ag+(aq)+NO3−(aq) ⟶ AgCl(s)+Na+(aq)+NO3−(aq) iii. CH3OH(g)+O2(g) ⟶ CO2(g)+H2O(g) iv. 2H2O(l) ⟶ 2H2(g)+O2(g) v. H+(aq)+OH−(aq)⟶ H2O(l)

Answers

Answer:

The answer is "Option i"

Explanation:

In this question, only option (i) is correct, and others were wrong which can be defined as follows:

In option (ii):

[tex]Na^+\ (aq)+Cl^- \ (aq) +Ag^+ \ (aq)+NO_3^- \ (aq) \to AgCl\ (s)+Na^+ \ (aq)+NO_3^-\ (aq) \\\\[/tex]

It is the complete ionic equation.

In option (iii):

[tex]CH_3OH\ (g)+O_2\ (g) \to CO_2\ (g)+H_2O\ (g)[/tex]

It is the combustion reaction but a not balanced equation.

In option (iv):

[tex]2H_2O\ (l) \to 2H_2\ (g)+O_2\ (g)[/tex]

It is the  decomposition equation.

In option (v):

[tex]H^+\ (aq) +OH^-\ (aq)\to H_2O\ (l)[/tex]

It is the complete ionic equation.

A pupil has drawn the electronic structure of fluorine and the diagram is shown below. However,
mistakes have been made. State three mistakes that have been made.

Fl atomic number: 9
Fl atomic mass: 10

(ps i have two of these but can’t figure out the last)

Answers

Answer:

The number of electrons in the orbit is wrong they have to be 9 and not 10since flourine is in group 7 the number of electrons in the outer most shell has to be 7 and not 2the first shell has 8 instead of 2 electrons

I hope this helps

Which sentence describes existing cells?


All cells, once formed, continue to live forever.


All cells come from previously existing cells.


All the cells that are on Earth have always been here.


All cells develop from the remains of other cells.

Answers

Hdhzhhw bzJijw d diaiwor
I believe it would be the second one

1 atm is equal to
O 1 mmHg
• 14.7 mmHg
• 76 mmHg
© 760 mmHg

Answers

Answer:

C 760 mm of hg

because this is the atmospheric pressure at sea level

the text of oxygen gas in the laboratory ​

Answers

Explanation:in testing for oxygen a glowing splint is used.

the glowing splint is brought in the presence of the test tube containing the gas

the glowing splint rekindles or lights up showing that oxygen is present.

this is a positive test because oxygen supports burning or combustion

If 16.4 grams of calcium nitrate is heated as shown in the reaction:

2Ca(NO3)2 -> 2CaO + 4NO2 + O2.

Calculate the volume of nitrogen dioxide produced at STP.​

Answers

Answer:

7.2

Explanation:

you first have to find the number of moles of nitrogen dioxide by using the number of moles for calcium nitrate and the mole to mole ratios

number of moles of calcium nitrate=mass/mm

=16.4/102

=0.16g/mol

then you use the mole to mole ratios

2 : 4

0.16: x

2x/2=0.64/2

x=0.32g/moles of nitrogen dioxide

then you use the formula for the volume

v=22.4n

=22.4×0.32

=7.2

I hope this helps

True or false, The universal gas constant, R, is . 0821 when we use mm Hg as our unit for pressure

Answers

Answer:

False

Explanation:

R = gas constant = 0.0821 atm•L/mol•K

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