Considering the definition of enthalpy of reaction, the correct answer is option C. a reaction with a negative enthalpy indicates that the reaction is exothermic.
Definition of enthalpy of reactionThe enthalpy of a chemical reaction as the heat absorbed or released when chemicals are transformed into a chemical reaction and it occurs at constant pressure.
The enthalpy is an extensive property, that is, it depends on the amount of matter present.
Finally, it must be taken into account that:
A reaction is called exothermic if its enthalpy of reaction is negative (that is, if the system gives up heat).A reaction is called endothermic if its enthalpy of reaction is positive (that is, if the system absorbs heat).SummaryIn summary, a reaction with a negative enthalpy indicates that the reaction is exothermic.
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How much heat is added if .0948g of water is increased in temperature by .728 degrees C?
.289 J
.803 J
1.46 J
.055 J
Answer:
0.289J of heat are added
Explanation:
We can relate the change in heat of a substance with its increasing in temperature using the equation:
q = m*ΔT*S
Where Q is change in heat
m is mass of substance (In this case, 0.0948g of water)
ΔT = 0.728°C
S is specific heat (For water, 4.184J/g°C)
Replacing:
q = 0.0948g*0.728°C*4.184J/g°C
q = 0.289J of heat are added
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
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
PLZ HELP ME Which of the following is the process by which chloroplasts use carbon dioxide, water, and sunlight to produce sugars and oxygen?
A. Photosynthesis
B. Cellular respiration
c. Reproduction
D. Homeostasis
Answer:
a
Explanation:
The unit of force newton is a derived unit.Why?
Answer:
Why is the unit of force called a derived unit? That's because the Newton is defined in terms of other units which are more fundamental. One Newton is the force required to accelerate a mass of one kilogramme at the rate of one metre per second squared.
A fixed mass of gas has a volume of 92 cm cube and 3 degrees Celsius. What will be its volume at 18 degrees celsius if the pressure remains constant?
Answer:
94.8454
Explanation:
Let volume be V
Let Temperature be T
V1= 92
T1= 3C but to kelvin 273+3= 300K
V2= ?
T2= 18 C but to kelvin 18+273= 291
[tex] \frac{v1}{t1} = \frac{v2}{t2} [/tex]
[tex] \frac{92}{300} = \frac{v2}{291} [/tex]
[tex]v2 \times 300 = 92 \times 291[/tex]
[tex]v2 = \frac{92 \times 291}{300} [/tex]
[tex]v2 = 94.8454[/tex]
solution is an example of______mixtures
Answer:
homogeneous mixture must be the answer
2 Figure 3.1 shows two different forms of carbon, A and B.
A
B
Figure 3.1
a Name the two forms of carbon shown.
Answer:
show the pictures pls specify
Question 2: thanks!!!
Balance in basic solution: O2(g) + Cr³+ (aq) → H₂O2 (1) + Cr₂O7²- (aq)
cr2o72+H2o2-(r3+o2)
Explanation:
r62o72+H2o2-(r3+o2)
Which reaction occurs at the cathode in an electrochemical cell?
A. Cu(s) → Cu2+(aq) + 2e
B. Cu2+(aq) + H2(g) → Cu(s) + 2H+(aq)
C. Cu(s) + 2H+(aq) → Cu2+(aq) + H2(g)
D. Cu2+(aq) + 2e → Cu(s)
Answer:
I could be wrong but I say it's letter b
Explanation:
I hope you have an great night
what is the most appropriate unit to measure the following; the length of a football field. b) the diameter of a tennis ball
Explanation:
a) m (metre)
b) mm (millimeter)
calculate the maximum mass of ethanol that could be obtained from 30.0g of glucose
Answer:
15.3g
Explanation:
C6H12O6 → 2C2H5OH + 2CO2
1 mol C6H12O6 = 180g
1 mol CH3-CH2-OH = 46g
From 180g glucose ethanol can get = 92g
30g glucose ethanol gives us = (92*30)/180 = 15.33g
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Chlorine and oxygen are both gases at room temperature. What are some characteristic properties of chlorine that distinguish it from oxygen?
Answer:
Well one characteristic is electical energy transforms into thermal energy and gases and the state of matter(one of the distinct form i which matter exist)
HF or HCl which can form the hydrogen bond? Explain your answer.
Answer:
can only form one hydrogen bond each
Explanation:
can only form one hydrogen bond each
Identify any three acids.
Identify any three bases.
Which factors ALL increase reaction rate?
decrease temperature, stir, increase surface area, remove catalyst
none of these
increase temperature, increase surface area, add catalyst, stir
increase temperature, stir, decrease surface area, add catalyst
Answer:
increase temperature, increase surface areas, add catalyst, stir
The rate of reaction can be increased with the increase in temperature, surface area, adding catalyst and allowing stirring. Thus, option C is correct.
What is rate of reaction?The rate of reaction is given as the rate of formation of product or the rate of disappearance of reactant in unit time.
The rate of reaction can be affected with:
Increase in temperature - It will increase the collisions between the reactants, and thereby the rate.Increase in surface area - It results in increased interaction of the reactant molecules for the formation of product.Catalyst - It lowers the activation energy of the reactant, and thereby increases the rate of reaction.Stirring - It mediates the increase in the collisions and the surface area, and resulting in increased rate of reaction.Thus, the rate of reaction can be increased with the increase in temperature, surface area, adding catalyst and allowing stirring. Thus, option C is correct.
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In a hospital, bags of saline solution are used to rehydrate patients. They are made by dissolving a specific amount of salt in water. What is the solvent in the saline solution?
A. Bag
B. Patient
C. Saline
D. Water
Water is the solvent in the saline solution. Hence, option D is correct.
What is the solute?A solute is something being dissolved, a solvent is a thing dissolving the item, and the solution is the mixture of the two items.
In a hospital, bags of saline solution are used to rehydrate patients. They are made by dissolving a specific amount of salt in water. Water is the solvent in the saline solution.
Hence, option D is correct.
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one similarity between physics and chemistry is...
Answer:
They are branch of science.
Explanation:
hope this helps
Answer:
Branch's of science yk
Explanation:
I'm smart lol
Explain which intermolecular force is primarily responsible for the unusually high boiling point of H2OH2O. Compare the strengths of intermolecular forces of attraction present in a sample of liquid water to the strengths of intermolecular forces of attraction present in liquid samples of H2SH2S, H2SeH2Se, and H2TeH2Te. Justify your answer using the information presented in both tables, and complete the statements below.
Answer:
See explanation
Explanation:
Intermolecular forces are forces of attraction that exist between molecules of a substance in a particular state of matter.
The dominant intermolecular force of attraction in H2O is the hydrogen bond. The hydrogen bond exists between molecules of a substance when the substance is made of hydrogen atoms bonded to atoms of a highly electronegative element. Hence, strong hydrogen bonding accounts for the high boiling point of water.
The magnitude of hydrogen bonding between molecules depends on the electro negativity of the atoms to which hydrogen is bonded.
The more the electro negativity of the atoms to which hydrogen is bonded, the greater the magnitude of intermolecular hydrogen bonding.
Since the electro negativity of elements decrease down the group, the strength of intermolecular hydrogen bonding between the molecules decreases as follows;
H2O> H2S> H2Se> H2Te
Classify each area of study as being a branch of science or not a branch of science. If you're unsure, take your best guess.
Drag each tile to the correct location.
SCIENCE
NOT SCIENCE
astronomy
astrology
biology
chemistry
geology
physics
theology
Answer: Science : Chemistry, astronomy , biology , physics , biology ,geology. Notscience : Astrology and theology
Explanation: Astrology and theology are non scientific areas of study.
If I add sugar into water then _________________
Pls help
Explanation:
When adding sugar to water it became a syrupy solution. Here sugar acts as solute, the water acts as solvent and syrupy acts as solution. When adding sugar to water, the disaccharide of sucrose is converted into monosaccharides of glucose and fructose
Answer:
syrupy solution
Write the relation of M3 with its multiples
Explanation:
HI friends good morning
What is the molecular geometry of a molecule made of two atoms that share one pair of electrons and have no lone electrons pairs?
trigonal pyramidal
linear
trigonal planar
bent
Answer:
linear
Explanation:
Actually I consulted various sources too and that was the most sought answer,I just decided to answer you before studying it too
balance the equation:2Na+3H2O-2NaOH+H2
Answer:
2Na + 2H2O → 2NaOH + H2
Explanation:
A balanced equation is an equation for a chemical reaction in which the number of atoms for each element in the reaction and the total charge are the same for both the reactants and the products.
Differentiate between emperical and
molecular formula. Give an example of
a substance having different emperical
and molecular formula
Answer:
Here’s an example:
CH (methylene) is the empirical formula.
C2H2 is a molecular formula. It is a gas called Ethyne.
C8H8 is an oily liquid called Styrene. It is also a molecular formula.
Now compare: even though the empirical formula for these compounds is the same, they have different molecular formulas and different properties.
Explanation:
Some background information:
The empirical formula is the formula with the lowest whole number ratio of an element in a compound. A molecular formula is the chemical formula of a (molecular) compound. The molecular formula gives us the exact number of atoms or moles in that compound.
I have attached pictures for a better understanding of the empirical formula.
For the reaction 2HNO3 + Mg(OH)2 + Mg(NO3)2 + 2H20, how many
grams of magnesium nitrate are produced from 3.54 mol of nitric
acid, HNO3?
O a. 220
O b. 263
O c. 1050
O d. 175
Answer:
B
Explanation:
to make 400 gram solution with a mass by a mass concentration of 6 % how much salt and water you need to mix
Answer:
[tex]400 \div 6 \\ \\ [/tex]
why is the Dna molecule able to open up and close?
Answer:
The breaking of the hydrogen bonds due to the force relieves the torsional stress stored in a double helix. As a result, the nucleotide strands rotate more freely about the axis of a helix and start unwinding. ... The DNA unzipping and the DNA unwinding result in a structural transformation from dsDNA to ssDNA.
Identify the correct mole ratio for each substance.
Sodium chloride (NaCl)
Na:Cl = 1: _
Ammonium nitrate(NH.NO3)
H:0 = 4: _
Answer:
The mole ratio of H : O in ammonium nitrate is 4 : 3.
Explanation:
We are given a compound named ammonium nitrate having formula
There are 3 elements in this compound which are nitrogen, hydrogen and oxygen.
To calculate the mole ratio, we write the ratio of their subscripts. For this compound,
Type the correct answer in the box. Express your answer to two significant figures. You are performing a reaction with 1.7 moles of hydroiodic acid and 3.43 moles of zinc bromide: 2HI + ZnBr2 → 2HBr + ZnI2. How many moles of zinc iodide can be made? The theoretical yield is moles of zinc iodide.
Answer:
1.34 34343 he did
Explanation:
i did the test
Answer:
0.85
Explanation:
