an unknown substance undergoes a chemical chance that gives off heat. which of the following is true
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.How is chemical sedimentary rock different from detrital sedimentary rock?
Chemical sedimentary rock and detrital sedimentary rock differ in terms of their formation and composition.
Explanation:Chemical sedimentary rock and detrital sedimentary rock are different in terms of how they form and their composition. Chemical sedimentary rocks are formed when dissolved minerals in water precipitate and solidify. Examples of chemical sedimentary rocks include limestone and rock salt. On the other hand, detrital sedimentary rocks are formed from the accumulation and lithification of fragments of other rocks. Examples of detrital sedimentary rocks include sandstone and shale.
How do you figure out the number of protons electrons and neutrons of 7Li+
The number of protons, electrons, and neutrons in the 7Li+ ion can be determined by its atomic number and mass number. It has 3 protons, 3 electrons, and 4 neutrons.
Explanation:Lithium-7 has three protons and four neutrons within its nucleus, making its mass number 7 and its atomic number 3. This means there are 3 protons, 3 electrons, and 4 neutrons in the 7Li+ ion.
Learn more about Atomic Structure here:https://brainly.com/question/33054877
#SPJ2
Roberto and his sister had a garden in the backyard. Every spring they grew strawberries, like the plant you see here. Plants make their own food through the process of photosynthesis. What non-living parts of this backyard ecosystem are needed for the plant to survive?
If a sample of gold is a cube what is the length of each edge in centimeters
To find the edge length of a cube made of gold, divide the mass of the gold sample by its density and take the cube root of the result.
Explanation:The edge length of a sample of gold, if it is in the form of a cube, can be determined using the concept of density. The density of gold is 19.3 g/cm³. To find the edge length, we need to divide the mass of the gold sample by its density. For example, if the mass of the gold sample is 10 grams, the volume is 10 g / 19.3 g/cm³ = 0.52 cm³. Since the sample is a cube, all three dimensions are equal, so the edge length would be the cube root of the volume. In this case, the edge length would be approximately 0.8 cm.
What is the mass, in grams, of a pure gold cube that has a volume of 3.20 cm3?
Final answer:
The mass of a pure gold cube with a volume of 3.20 cm³ is 61.76 grams. Using the density of gold (19.3 g/cm³), the mass is calculated by multiplying density by volume, with the final answer rounded to three significant figures as 61.8 grams.
Explanation:
To calculate the mass of a pure gold cube with a given volume, you use the density of gold. The density (d) of gold is known to be 19.3 g/cm³. Thus, if the volume of the gold cube is 3.20 cm³, the mass (m) is calculated as follows:
m = d × V
Where m is the mass, d is the density, and V is the volume. Plugging in the values:
m = 19.3 g/cm³ × 3.20 cm³
m = 61.76 grams
Therefore, the mass of the gold cube is 61.76 grams. We limit our final answer to three significant figures, so the mass is 61.8 grams.
if an elements atomic mass is 70 and it has 39 neutrons how many protobs does it have? What element is this?
The element has 31 protons based on the given information, but its specific identity cannot be determined.
Explanation:The number of protons in an atom is determined by its atomic number. In this case, the element has 39 neutrons and a total atomic mass of 70. To find the number of protons, we subtract the number of neutrons from the atomic mass. So, the element has 31 protons.
The atomic number of an element determines its identity on the periodic table. However, with only the number of neutrons and the atomic mass given, it is impossible to determine the exact identity of the element. More information is needed to identify the element.
Learn more about atomic structure here:https://brainly.com/question/33054877
#SPJ2
(a) the characteristic odor of pineapple is due to ethyl butyrate, a compound containing carbon, hydrogen, and oxygen. combustion of 4.17 mg of ethyl butyrate produces 9.48 mg of co2 and 3.87 mg of h2o. what is the empirical formula of the compound?
By stoichiometry and assume that:
CxH2xOy + zO2 -> xCO2 + xH2O
CO2: 9.48/44 = 0.215 mmol
H2O: 3.87/18 = 0.215 mmol
mass of C = 0.215 * 12 = 2.58 mg
mass of H = 0.215 * 2 * 1 = 0.43 mg
mass of O in ethylbutyrate = 4.17 - 2.58 - 0.43 = 1.11 mg
So C/O = 2.58/1.11 ≈ 3
Thus we have C3H6O
Answer: The empirical formula for the given compound is [tex]C_3H_6O[/tex]
Explanation:
The chemical equation for the combustion of hydrocarbon having carbon, hydrogen and oxygen follows:
[tex]C_xH_yO_z+O_2\rightarrow CO_2+H_2O[/tex]
where, 'x', 'y' and 'z' are the subscripts of Carbon, hydrogen and oxygen respectively.
We are given:
Mass of [tex]CO_2=9.48mg=9.48\times 10^{-3}g[/tex]
Mass of [tex]H_2O=3.87mg=3.87\times 10^{-3}g[/tex]
We know that:
Molar mass of carbon dioxide = 44 g/mol
Molar mass of water = 18 g/mol
For calculating the mass of carbon:
In 44 g of carbon dioxide, 12 g of carbon is contained.
So, in [tex]9.48\times 10^{-3}g[/tex] of carbon dioxide, [tex]\frac{12}{44}\times 9.48\times 10^{-3}=2.58\times 10^{-3}g[/tex] of carbon will be contained.
For calculating the mass of hydrogen:
In 18 g of water, 2 g of hydrogen is contained.
So, in [tex]3.87\times 10^{-3}g[/tex] of water, [tex]\frac{2}{18}\times 3.87\times 10^{-3}=4.30\times 10^{-4}g[/tex] of hydrogen will be contained.
For calculating the mass of oxygen:
Mass of oxygen in the compound = [tex](4.17\times 10^{-3})-[(2.58\times 10^{-3})+(4.30\times 10^{-4})]=1.16\times 10^{-3}g[/tex]
To formulate the empirical formula, we need to follow some steps:
Step 1: Converting the given masses into moles.
Moles of Carbon =[tex]\frac{\text{Given mass of Carbon}}{\text{Molar mass of Carbon}}=\frac{2.58\times 10^{-3}g}{12g/mole}=2.15\times 10^{-4}moles[/tex]
Moles of Hydrogen = [tex]\frac{\text{Given mass of Hydrogen}}{\text{Molar mass of Hydrogen}}=\frac{4.30\times 10^{-4}g}{1g/mole}=4.30\times 10^{-4}moles[/tex]
Moles of Oxygen = [tex]\frac{\text{Given mass of oxygen}}{\text{Molar mass of oxygen}}=\frac{1.16\times 10^{-3}g}{16g/mole}=7.25\times 10^{-5}moles[/tex]
Step 2: Calculating the mole ratio of the given elements.
For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is [tex]7.25\times 10^{-5}[/tex] moles.
For Carbon = [tex]\frac{2.15\times 10^{-4}}{7.25\times 10^{-5}}=2.96\approx 3[/tex]
For Hydrogen = [tex]\frac{4.30\times 10^{-4}}{7.25\times 10^{-5}}=5.93\approx 6[/tex]
For Oxygen = [tex]\frac{7.25\times 10^{-5}}{7.25\times 10^{-5}}=1[/tex]
Step 3: Taking the mole ratio as their subscripts.
The ratio of C : H : O = 3 : 6 : 1
Hence, the empirical formula for the given compound is [tex]C_3H_6O_1=C_3H_6O[/tex]
Why is it impossible to contain gaseous iron in a glass container?
In its standard temperature and pressure, iron would exist as a solid. Therefore to make it into gas, we must heat it beyond its boiling point which is around 2,862°C. At that temperature, ordinary glass container would readily melt. Hence, it is impossible to contain gaseous iron in a glass container.
Although the nucleus of an atom is very important, it is the ___ of the atom that determine its chemical properties
It's the electrons of an atom that determine its chemical properties. Electrons participate in chemical reactions—and it's these electron interactions that govern the atom's chemistry. For instance, chlorine's reactions stem from its desire to gain an extra electron.
Explanation:Although the nucleus of an atom is indeed very important, it is the electrons of the atom that ultimately determine its chemical properties. This is because electrons involve in the chemical reactions.
In order for any chemical reaction to occur, there must be a movement, exchange or sharing of the electrons between two or more atoms. It's these electron interactions that govern the chemistry of the atom, hence determining its chemical properties.
For example, chlorine (Cl) has 7 electrons in its outermost shell and would prefer to gain an additional electron to achieve a complete outer shell. This electron 'hunger' is what fuels chlorine's reactions with other elements and compounds, thus determining its chemical properties.
Learn more about Atomic Structure here:
https://brainly.com/question/7328982
#SPJ6
Selenous acid is diprotic it can react with sodium hydroxide in steps write equations (in molecular form) for the two steps of the reaction
The chemical formula for the selenous acid is H2SeO3. Its reaction with sodium hydroxide, which has a chemical formula of NaOH, will be a neutralization reaction forming a salt and water. This is depicted below.
H2SeO3 + NaOH à Na2SeO3 + H2O
If we are to balance the chemical reaction then, we will have a final answer of,
H2SeO3 + 2NaOH à Na2SeO3 + 2H2O
Which of the following will occur soon after a population of prey increases slightly in size?
A) Predator population will remain the same.
B) Predator population will decrease greatly.
C) Predator population will decrease slightly.
D) Predator population will increase greatly.
E) Predator population will increase slightly.
Answer:
The Answer is E
Explanation:
Got it right on the test.
During photosynthesis, sunlight shining on a plant is absorbed. Through several chemical reactions, the plant produces sugar, a high-energy compound, from simpler substances. What energy transformation occurs during this process?
Answer: radiant energy to chemical energy
Explanation:-
Radiant energy is the energy of electromagnetic waves.
Chemical energy is the energy stored in the bonds of molecules.
Photosynthesis is a phenomenon in which green plants containing chlorophyll use sunlight as a source of energy to convert carbon dioxide and water to form glucose and oxygen.
Photosynthesis is the process used by plants, algae and certain bacteria to convert energy from sunlight called as radiant energy and turn it into chemical energy in the form of glucose which is used as a source of energy by many organisms.
[tex]6CO_2+6H_2O\overset{sunlight}\rightarrow C_6H_{12}O_6+6O_2[/tex]
Can a chemical change be something heating up?
Suppose you have an atom composed of 19 protons, 20 neutrons and 19 electrons. what is the mass of this atom?
How could you determine the correct temperature range, salt concentration, and ph for a specific enzyme?
Use the periodic table entry below to answer the following question.
What is the atomic mass of the element cobalt (Co)?
27
31
59
31.71
The fundamental difference between covalent bonds and ionic bonds is that in covalent bonds __________ whereas in ionic bonds __________.
Covalent bonds involve the sharing of electrons between atoms, while ionic bonds involve the transfer of electrons from one atom to another.
Explanation:The fundamental difference between covalent bonds and ionic bonds is that in covalent bonds, electrons are shared between atoms, whereas in ionic bonds, electrons are transferred from one atom to another.
In covalent bonds, the atoms are nonmetals and they share electrons to achieve a stable electron configuration. Examples include the bond between two hydrogen atoms in a hydrogen molecule (H2) and the bond between carbon and oxygen in carbon dioxide (CO2).
In ionic bonds, one atom loses electrons to become a positively charged ion (cation), while another atom gains those electrons to become a negatively charged ion (anion). These oppositely charged ions are then attracted to each other and form an ionic bond. An example is the bond between sodium (Na+) and chlorine (Cl-) in sodium chloride (NaCl).
Learn more about Covalent bonds and Ionic bonds here:https://brainly.com/question/32827812
#SPJ12
Select the compound that is not organic.
1. Sucrose
2. Methane
3. Urea
4. Sodium Chloride
Answer:
Sodium chloride.
Explanation:
The organic compounds are compounds of carbon. They may have some other atoms like hydrogen, oxygen, sulfur, nitrogen, halogens etc. However the skeleton is of carbon only.
The simplest organic compound is methane (which is a hydrocarbon).
Sucrose is a disaccharide of glucose and fructose. It is an organic compound.
Urea is NH₂CONH₂, again an organic compound.
While Sodium chloride is NaCl, which has no carbon and it is an ionic inorganic compound.
Sort these elements into pairs that would most likely exhibit similar chemical properties Br ,Mg ,F ,Sr ,S ,O
Final answer:
Similar chemical properties in elements arise from their groupings in the periodic table. Bromine and Fluorine are paired as halogens; Magnesium and Strontium as alkaline earth metals; and Sulfur and Oxygen as chalcogens.
Explanation:
Elements that exhibit similar chemical properties are often found in the same group or family on the periodic table. The elements provided can be sorted into pairs based on their chemical behaviors and position in the periodic table:
Bromine (Br) and Fluorine (F): Both are halogens found in Group VII, known for their reactivity and tendency to form compounds by gaining one electron.Magnesium (Mg) and Strontium (Sr): These are alkaline earth metals found in Group II, which are shiny and good conductors of heat and electricity, with each forming compounds with oxygen in a ratio of one of their atoms to one oxygen atom.Sulfur (S) and Oxygen (O): Both belong to Group VI (the chalcogens) and can form compounds by gaining two electrons.In summary, similar properties in elements are a result of their position within the same group on the periodic table. For example, bromine and fluorine are both halogens, while magnesium and strontium are alkaline earth metals.
What is the mass number of an ion with 109 electrons, 157 neutrons, and a +1 charge?
a hockey player has the puck in the corner of the rink. an opposing player muscles him aside and emerges with the puck. this situation is most analogous to which kind of reaction?
Answer: Single displacement
Explanation:
A single replacement reaction is one in which a more reactive element displaces a less reactive element from its salt solution. Thus one element should be different from another element.
A general single displacement reaction can be represented as :
[tex]A+BC\rightarrow AC+B[/tex]
Thus if A is more reactive than b, then A can displace B from its position and can combine with C to give AC and B.
Given:A hockey player has the puck in the corner of the rink. An opposing player muscles him aside and emerges with the puck. Thus it is similar to single displacement reaction.
Water molecules are __________.
a. composed of atoms joined by stable polar covalent bonds
b. attracted to each other because of their polar nature
c. capable of interacting with ions and polar molecules because of water being a polar molecule
d. all of the above are true
The compound zinc fluoride is a strong electrolyte. write the transformation that occurs when solid zinc fluoride dissolves in water.
When solid zinc fluoride (ZnF2) dissolves in water, it dissociates into its constituent ions to form aqueous zinc ions (Zn^2+) and fluoride ions (F^-). This transformation represents a physical change known as dissociation. This reaction is typical for strong electrolytes like zinc fluoride due to the ionic bonds within the compound.
Explanation:The compound zinc fluoride (ZnF2) is a strong electrolyte, which means that it completely dissociates into its constituent ions when dissolved in water. The process of dissociation occurs when the ions in the solid separate and disperse uniformly throughout the solution. This is facilitated by water molecules that surround and solvate the ions, reducing the strong electrostatic forces between them.
When solid zinc fluoride dissolves in water, it forms aqueous zinc ions (Zn^2+) and fluoride ions (F^-). This can be represented by the equation:
ZnF2 (s) -> Zn^2+ (aq) + 2F^- (aq)
This transformation is a physical change known as dissociation. The term 'aq' denotes that the ions are in an aqueous solution, indicating that they have been solvated by water molecules. It's noteworthy that the compound zinc fluoride, by nature of it being an ionic bond, is a strong electrolyte, hence it will nearly completely dissociate when dissolved in water.
Learn more about Zinc Fluoride Dissolution here:https://brainly.com/question/5452058
Elements in the same group of the periodic table typically have ________.
Two atoms of the same element must have the same number of _____. two atoms of the same element must have the same number of _____. electrons protons neutrons plus protons neutrons
Answer: Option (b) is the correct answer.
Explanation:
When two atoms of the same element has different number of neutrons but same number of protons then it is known as an isotope.
For example, isotopes of carbon are [tex]^{12}_{6}C[/tex] and [tex]^{13}_{6}C[/tex].
Also, when two atoms of the same element have same number of protons then their chemical properties remain the same.
Therefore, we can conclude that two atoms of the same element must have the same number of protons.
Why does a solid turn into a liquid when heat is added?
The molar mass of iron oxide (Fe2O3) is 159.7 g/mol. What is the correct way to write the molar mass of iron oxide as a conversion factor?
the answer is C 159.7g Fe2O3/1 mol Fe2 O3
When writing the conversion factor for the molar mass of Fe2O3, it will be written as:
159.7 g Fe2O3 / 1 mol What is the conversion factor of iron oxide (Fe2O3) whose molar mass is 159.7 g/mol?The molar mass of a substance is the mass of one mole of that substance.
The molar mass of of iron oxide (Fe2O3) is 159.7 g/mol.
This means that 1 mole of iron oxide (Fe2O3) has a mass of 159.7 g.
Therefore, in writing the conversion factor, it will be written as:
159.7 g Fe2O3 / 1 molLearn more about molar mass at: https://brainly.com/question/15476873
Which compound is a carbohydrate?
A) sugar
B) water
C) olive oil
D) amino acid
Prepare approximately .1n hcl by putting the correct amount of concentrated acid in a glass bottle and