The correct statement for a chemical change that gives off heat is that the molecule types change and the process is exothermic, as energy is released to the surroundings.
When an unknown substance undergoes a chemical change that gives off heat, the process is exothermic, and the types of molecules before and after the change are different. A chemical change that releases heat indicates that energy is a product of the reaction.
This is contrasted with an endothermic process where heat is absorbed, and the surroundings become colder. In exothermic reactions, bonds are formed which release more energy than the energy needed to break bonds in the reactants, hence the heat given off to the surroundings.
The correct statement for a chemical change that produces heat is: The types of molecules of the substance before and after the chemical change are different, and the change was exothermic.
Complete Question - An unknown substance undergoes a chemical change that gives off heat. Which statement is true?
The types of molecules of the substance before and after the chemical change are different, and the change was endothermic. The types of molecules of the substance before and after the chemical change are the same, and the change was exothermic. The types of molecules of the substance before and after the chemical change are the same, and the change was endothermic. The types of molecules of the substance before and after the chemical change are different, and the change was exothermic.Large molecules that contain carbon and are held together by covalent bonds are called
1 kg is equal to...
Options:
1) 103 hg.
2) 103 g.
3) 10-2 cg.
4) 10-2 g.
An element has three naturally occurring isotopes. Use the information below to calculate the weighted average atomic mass of the element, showing both the setup and the final answer for the calculation.
Isotope
Atomic Mass
Percent Abundance
I
39.96 u
99.59%
II
37.96 u
0.065%
III
35.97 u
0.336%
When the mineral dolomite (caco3·mgco3) is heated, it gives off carbon dioxide and forms a mixture of a metal oxide and a metal carbonate. which carbonate is formed?
What is the volume (in cubic inches) of 3.6 lb of titanium? The density of titanium is 4.51 g/cm3
To calculate the volume of titanium given its mass, you must first convert the mass from pounds to grams. Apply the formula volume=mass/density and then convert the volume from cubic centimeters to cubic inches. The volume of 3.6 lb of titanium rounded off to the nearest hundredth is 22.07 cubic inches.
Explanation:To calculate the volume of a substance, you need to use the formula:
volume = mass / density
Given the mass of titanium is 3.6 lb and the density is 4.51 g/cm³, you first need to convert the mass from pounds to grams (since the density is given in g/cm³). This can be done using the conversion factor: 1 lb = 453.59 g.
So, 3.6 lb = 3.6 x 453.59 g = 1632.924 g.
Then, apply the volume formula:
Volume = 1632.924 g / 4.51 g/cm³ = 361.847 cm³
Finally, convert the volume in cm³ to in³, using the conversion factor: 1 cm³ = 0.0610 in³.
So, the volume in in³ is: 361.847 cm³ = 361.847 x 0.0610 in³ = 22.0727 in³
Hence, the volume of 3.6 lb of titanium is approximately 22.07 cubic inches.
Learn more about Volume here:https://brainly.com/question/33318354
#SPJ12
What concentration of benzoic acid will have a ph of 4.0? (for benzoic acid, pka=4.20)?
Volume measurements will be made using a 25-ml graduated cylinder, which has major scale divisions marked every 2 ml and minor scale divisions every 0.2 ml. what is the estimated uncertainty in the volume measurements
Actually, the uncertainty point is when we have to estimate one place smaller than what the graduated cylinder can accurately read. So in this case, the smallest that we can accurately read is given by the minor marks of 0.2 mL. So if it is in between two minor marks we can only estimate the number, therefore the uncertainty is +/- 0.1ml.
Answer:
The estimated uncertainty is ±0.1 ml
Explanation:
Measurements are usually associated with uncertainty which depends on the instrument used or the procedure employed.
It is given that the graduated cylinder of volume 25 ml has a major scale marked every 2 ml and minor scale with 0.2 ml. In general measurements made with graduated cylinders can be estimated one decimal place beyond the smallest division. In this case, the volume of the liquid can be read to the nearest 0.1 division. Hence, the uncertainty would be ± 0.1 ml.
What is the volume of a solution that has a specific gravity of 1.2 and a mass of 185 g?
Which of these ions have six d electrons in the outermost d subs hell
Ions with six d electrons in the outermost d subshell can be found in transition metal elements such as Cr³+(d³), Co²+(d²), Ni²+(d³), Cu²+(d³), and Zn²+(d¹⁰)
Explanation:The ions with six d electrons in the outermost d subshell are typically found in the transition metal elements.
For example, the ion with six d electrons in the outermost subshell is Cr³+(d³).
Other ions with six d electrons in the outermost subshell include Co²+(d²), Ni²+(d³), Cu²+(d³), and Zn²+(d¹⁰).
Learn more about Ions with six d electrons in outermost d subshell here:https://brainly.com/question/4964459
#SPJ3
Write a net ionic equation to show how codeine, c18h21o3n, behaves as a base in water.
Actually, the ionic equation for this is a reversible equation since codeine is a weak base. Any weak base or weak acids do not completely dissociate which makes them a reversible process. The ionic equation for this case is:
C18H21O3N + H3O+ <=> C18H21O3NH+ + H2O
These reactions can also be reversed, breaking the large molecules into its individual molecules. what substance would need to be added in order to reverse the reaction
Is helium a homogeneous or heterogeneous mixture or compound or element?
How many moles of aspartame are present in 5.00 mg of aspartame?
To find the number of moles in a given mass, convert the mass to grams (if necessary) and divide by the molar mass. Hence, in 5.00 mg of aspartame, there are approximately 1.70 x 10^-5 moles.
Explanation:To calculate the number of moles of aspartame in a given mass, we would use the molar mass of aspartame. First, we need to convert the mass from milligrams to grams because molar mass is usually given in g/mol. As 1 gram (g) is equal to 1000 milligrams (mg), 5.00 mg is equal to 0.005 g.
The molar mass of aspartame (C14H18N2O5) is approximately 294.31 g/mol. After converting the mass to grams, we use the formula: number of moles = mass (g) / molar mass (g/mol).
Therefore, the number of moles of aspartame in 5.00 mg is 0.005g / 294.31 g/mol = 1.70 x 10^-5 mol. So, there are roughly 1.70 x 10^-5 moles of aspartame in 5.00 mg.
Learn more about Moles of Aspartame here:https://brainly.com/question/30337261
#SPJ12
Which subatomic particle is the identity of the atom and why?
Classify each of these soluble solutes as a strong electrolyte, a weak electrolyte, or a nonelectrolyte. solutes formula nitric acid hno3 lithium hydroxide lioh hydrofluoric acid hf ammonia nh3 potassium chloride kcl ethanol c2h5oh glucose c6h12o6
Final answer:
Nitric acid and lithium hydroxide are classified as strong electrolytes, meaning they fully dissociate into ions in solution. Hydrofluoric acid and ammonia are weak electrolytes, partially dissociating into ions. Ethanol and glucose are nonelectrolytes, dissolving without forming ions.
Explanation:
When classifying solutes as strong electrolytes, weak electrolytes, or nonelectrolytes, we examine how they dissociate in water. A strong electrolyte dissociates completely into ions, a weak electrolyte only partially dissociates, and a nonelectrolyte does not dissociate at all in solution.
Nitric acid (HNO3) is a strong electrolyte because it dissociates completely into H+ and NO3- ions in aqueous solution.Lithium hydroxide (LiOH) is also a strong electrolyte, as it dissociates into Li+ and OH- ions when dissolved in water.Hydrofluoric acid (HF) is a weak electrolyte because it only partially dissociates into H+ and F- ions.Ammonia (NH3), when dissolved in water, forms ammonium (NH4+) and hydroxide (OH-) ions, but because the reaction is reversible and the degree of dissociation is not complete, it is also considered a weak electrolyte.Potassium chloride (KCl) is a strong electrolyte that fully dissociates into K+ and Cl- ions.Ethanol (C2H5OH) and glucose (C6H12O6) are both nonelectrolytes; they dissolve as molecules without forming ions in aqueous solution.The reaction of 1.250 g k with o2 forms 2.273 g of an oxide of potassium that is used in self-contained breathing devices. determine the formula for this oxide of potassium.
AgNO3(aq)+NaCl(aq)------>AgCl(s)+NaNO3(aq)
Name the chemical that are dissolved in water
In the reaction AgNO3(aq)+NaCl(aq)------>AgCl(s)+NaNO3(aq), the chemicals dissolved in water are AgNO3, NaCl, and NaNO3.
Explanation:In the chemical reaction AgNO3(aq)+NaCl(aq)------>AgCl(s)+NaNO3(aq), the chemicals that are dissolved in water, also known as aquatic solutions, are AgNO3 (Silver Nitrate) and NaCl (Sodium Chloride) on the reactant side, and NaNO3 (Sodium Nitrate) on the product side. These are shown with the (aq) notation which indicates they are aquatic, or dissolved in water.
The product AgCl (Silver Chloride), shown with the (s) notation, demonstrates that it precipitates, or forms a solid in the solution instead of dissolving in the water.
Learn more about Aquatic Solutions here:https://brainly.com/question/35489840
#SPJ2
Calculate the specific heat of a substance when 63j of energy are transferred as heat to an 8.0 g sample to raise it temperature from 314 k to 340 k
The formula for energy or enthalpy is:
E = m Cp (T2 – T1)
where E is energy = 63 J, m is mass = 8 g, Cp is the specific heat, T is temperature
63 J = 8 g * Cp * (340 K – 314 K)
Cp = 0.3 J / g K
Answer : The specific heat of substance is 0.30 J/g.K
Explanation :
Formula used :
[tex]Q=m\times c\times \Delta T[/tex]
or,
[tex]Q=m\times c\times (T_2-T_1)[/tex]
where,
Q = heat = 63 J
m = mass of substance = 8.0 g
[tex]C_w[/tex] = specific heat of substance = ?
[tex]T_1[/tex] = initial temperature = 314 K
[tex]T_2[/tex] = final temperature = 340 K
Now put all the given value in the above formula, we get:
[tex]63J=8.0g\times c\times (340-314)K[/tex]
[tex]c=0.30J/g.K[/tex]
Therefore, the specific heat of substance is 0.30 J/g.K
How does an elements period number related to the number of the energy level of its valence electrons?
Which of the following will hold its shape?
A. gas
B. solid
C. liquid
D. plasma
Answer:
Solid
Explanation:
A solid will retain its shape; the particles are not free to move around.
True or false? an element consists of only single atoms of that element.
The molecular structure of water contains two atoms of hydrogen and one atom of oxygen. When water reaches its boiling point and turns into water vapor, what happens to its molecular structure?
A. It remains the same
B. It changes the ratio of atoms
C. It forms bigger molecules
D. It forms lighter molecules
Thanks for helping! x
What is the volume of 12.8 g of a liquid that has a density of 0.789 g/mL?
Answer: The volume of liquid is 16.22 mL.
Explanation:
Density is defined as the ratio of mass of the object and volume of the object.
Mathematically,
[tex]\text{Density}=\frac{\text{Mass of the object}}{\text{Volume of the object}}[/tex]
We are given:
Density of liquid = [tex]0.789g/mL[/tex]
Mass of liquid = 12.8 g
Putting values in above equation, we get:
[tex]0.789g/mL=\frac{12.8g}{\text{Volume of liquid}}\\\\\text{Volume of liquid}=16.22mL[/tex]
Hence, the volume of liquid is 16.22 mL.
Which elements make up 96.3% of living things?
What color did the bromothymol blue indicator turn when it was added to the test tube containing citric acid?
The complete combustion of ethanol, c2h5oh(l), to form h2o(g) and co2(g) at constant pressure releases 1235 kj of heat per mole of c2h5oh. write a balanced equation for this reaction.
Since it was specifically stated that heat is released, therefore heat is located on the right side of the reaction equation. Also stating the states of each compound, the complete balanced reaction would be:
C2H5OH (l) + 3 02 (g) -----> 2 CO2 (g) + 3 H2O (g) + 1235 kJ
The balanced combustion reaction will be
[tex]\rm \bold {C_2H_5OH_ (_l_) + 3 0_2 _(_g_) \rightarrow 2 CO_2 _(_g_) + 3 H_2O (g) + 1235 kJ}[/tex]
To write a balanced equation
We will carefully put reactant in the left and product into the right. The energy released will be mentioned in right.The states of reactant and product will also mentioned.Hence, balanced reaction will be
[tex]\rm \bold {C_2H_5OH_ (_l_) + 3 0_2 _(_g_) \rightarrow 2 CO_2 _(_g_) + 3 H_2O (g) + 1235 kJ}[/tex]
To know more about chemical equation, refer to the link:
https://brainly.com/question/12271256?referrer=searchResults
According to the Gas Laws, you would changed temperature to change __________.
A. volume and pressure
B. mass and volume
C. weight and volume
D. gravity and volume
express 601 kg as an integer
601kg as integers can be written as 601000
Explanation:In mathematics an integer is a number that can be written without a fractional or decimal component. For example: 21, 4, and −2048 are integers; 9.75, 5½, and √2 are not integers. If zero comes in the middle of the integer it is taken into account but if it comes in the start then it is discarded. Similarly we have scientific notations and we know that kg is equal to 1000 so we can write 601 kg as 601000 which fulfills both the definition of integer and scientific notation.
601 kg expressed as an integer remains 601 kg, since it is already a whole number and does not require any conversion.
Explanation:To express 601 kg as an integer, we do not need to apply any conversions, as 601 kg is already an integer value. The term 'integer' refers to a whole number that is not a fraction or a decimal. Therefore, 601 kg is an integer as it stands. It's important to note that when measuring mass or weight, it's beneficial to use units that keep the number manageable and avoid unnecessary complexity, as described with the examples of different weight measurements and their ease based on the unit used.
What volume of 0.200 m h3po4 will completely react with 50.00 ml of 0.200 m naoh?
Propane has the formula c3h8. if a sample of propane contains 0.20 moles of c, how many moles of h are present?
Solving this problem only requires the knowledge of stoichiometry. We are given the compound propane C3H8. From the chemical formula, we can see that for every 3 moles of C, there are 8 moles of H. Therefore:
moles of H = 0.20 moles C * (8 moles H / 3 moles C)
moles of H = 0.53 moles H
Answer: In the given sample, 0.533 moles of hydrogen will be present.
Explanation:
We are given a chemical compound having formula [tex]C_3H_8[/tex]
We are provided with 0.20 moles of carbon atoms.
As, for every 3 moles of carbon atoms, 8 moles of hydrogen atoms are present.
So, for 0.20 moles of carbon atoms, [tex]\frac{8}{3}\times 0.20=0.533moles[/tex] of hydrogen atoms will be present.
Hence, in the given sample, 0.533 moles of hydrogen will be present.