Answer:
A. It is exothermic
Explanation:
Combustion is a chemical reaction in which a substance combines with oxygen present in air to produce carbon (iv) oxide and water as well release heat and light energy.Combustion is an exothermic process.
An exothermic reaction releases energy in the form of heat to the surroundings. The energy required to break bonds in the reactants is less than the energy required to form new bonds in the products in an exothermic reaction.
From the given options;
A. It is exothermic is determinable since the reaction is a combustion reaction
B. The bond making energy is more than 600 kJ is not certain because the mass of the wood being burnt is not given. Also, wood is not composed of a specific element that would be taking part in the reaction, rather it is composed of various substances.
C. It is endothermic. is wrong because combustion of wood is exothermic.
D. The bond breaking energy is more than 600 kJ is not certain because the mass of the wood being burnt is not given. Also, wood is not composed of a specific element that would be taking part in the reaction, rather is composed of many substances.
In the hydrogenation of oils the catalyst used is:
A. Pt
B. Ni
C. Fe
D. V2O5
Answer:
B
Explanation:
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I'll mark you brainliest if you answer first! - Iron filings and copper (II) sulphate solution are mixed together and they produce elemental copper and iron (II) sulphate solution. Based on the quantities of the reactants used in the experiment, determine which is the limiting reagent. For the excess reagent, determine how much in grams is left over. (2 grams of iron was used, and 7 grams of copper
Answer:
First, write an equation for the reaction involved.
Fe + CuSO4 ---> FeSO4 + Cu
Now, calculate the no. of moles added in the reaction. (n.o.m. = mass /molar mass)
No. of moles of Fe added = 2 / 55.8
= 0.0358 mol
No. of moles of CuSO4 = 7 / (63.5 +32.1+16x4)
= 0.04386 mol
From the equation, the mole ratio of Fe : CuSO4 = 1:1,
meaning 1 mole of Fe reacts with 1 mole of CuSO4.
It also indicates that the no. of moles reacted in Fe equals to the no. of moles reacted in CuSO4.
0.04386 > 0.0358
The no. of moles of CuSO4 is higher than that of Fe, meaning all moles of Fe will be reacted while not all CuSO4 reacts.
Hence Fe is the limiting reagent, and CuSO4 is in excess.
All 0.0358 moles of Fe reacts, meaning the no. of moles of CuSO4 left unreacted = 0.04386 - 0.0358
= 0.0080596mol
mass of CuSO4 unreacted = 0.0080596 x (63.5 +32.1+16x4)
= 1.28g
How do I write these decimal numbers in expanded form? 0.913, 0.205, 0.047, 0.480
Thanks! :)
Explanation:
To write a decimal in expanded form, write the number as a sum of its place values.
0.913 = 0.9 + 0.01 + 0.003
0.205 = 0.2 + 0.005
0.047 = 0.04 + 0.007
0.480 = 0.4 + 0.08
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What is the mass of 15% of solution of lime that is formed by dissolving 30g of calcium hydroxide in water?
Answer:
200 grams is the mass of 15% of the solution of lime that is formed by dissolving 30g of calcium hydroxide in water.
Explanation:
Mass of solution = M
Mass percentage of the solution of lime = 15%
Mass of lime or calcium hydroxide = m = 30 g
The Formula of mass percentage is given as :
[tex]m/m\%=\frac{m}{M}\times 100[/tex]
On substituting the values in ab above formula :
[tex]15\%=\frac{30 g}{M}\times 100[/tex]
[tex]M=\frac{30 g}{15}\times 100=200 g[/tex]
200 grams is the mass of 15% of the solution of lime that is formed by dissolving 30g of calcium hydroxide in water.
(4 marks)
A farmer distributed his cabbages as follows: A certain hospital received a quarter of the
total number of bags. A nearby school received half of the remainder. A green grocer
received a third of what the school received. What remained were six bags more than
what the green grocer received. How many bags of cabbages did the farmer have?
(3
Answer:
Explanation:
Let the farmer had n no of bags of cabbage .
given to hospital = n / 4
given to school = 1/2 x 3n /4
= 3n / 8
given to grocer = 1 / 3 x (3n / 8 )
= n / 8
No of bags distributed
= n / 4 + 3n / 8 + n / 8
= 6n / 8
Remaining bag
= n - 6n / 8
= 2n / 8
According to question
2n / 8 = 6 + n / 8
n / 8 = 6
n = 48 .
The correct increasing order of Bond angle is H2O < NH3 < BCl3 < CCl4 H2O < NH3 < CCl4 < BCl3 NH3 < H2O < BCl3 < CCl4 NH3 < BCl3 < CCl4 < H2O
Answer:
H2O < NH3 < CCl4 < BCl3
Explanation:
Bond angle of a molecule or an ion can be explained by two concepts which are either by their valence shell electron pair repulsion (VSEPR) model or hybridization.
The VSEPR model determines the total number of electron pairs surrounding the central atom of the species. All the electron pairs will orient themselves in such a way as to minimize the electrostatic repulsions between them. These repulsions hence determine the geometry of the covalent bond angles around the central atom.
Hence; as the number of lone pairs increases from zero to 2 the bond angles diminish progressively.
Hybridization is the mixing and blending of two or more pure atomic orbitals to form two or moe hybrid atomic orbitals which are identical in shape and energy. During the process of formation of these hybrid orbitals, The bonds formed i.e the sigma bond and the pi bond determines the bond angle of such compound.
From the given compounds;
H20 have a bond angle of 104.5°
NH3 have a bond angle of 107°
BCl3 have a bond angle of 120°
CCl4 have a bond angle of 109.5°
thus in an increasing order of bond angle:
H2O < NH3 < CCl4 < BCl3
A metal sample is heated and placed into the water in a calorimeter at room temperature. Which statement best describes how the calorimeter can be used to determine the specific heat capacity of the metal sample? Energy transfers to the metal from the water and calorimeter until they are all at room temperature. Energy transfers from the metal to the water and calorimeter until they are all at room temperature. Energy transfers to the metal from the water and calorimeter until they all reach a single temperature. Energy transfers from the metal to the water and calorimeter until they all reach a single temperature.
Answer:
Energy transfers from the metal to the water and calorimeter until they are all at room temperature.
Explanation:
Calorimetry is the process that is used to determine the amount of heat that has been transferred in any process. In any chemical or physical process, the amount of energy is required. This energy is measured by the process of calorimetry. A calorimeter is a device that is used in this process. The heat that has been used in the process is measured and the change in the temperature is noted.
Answer:
b
Explanation:
What is the acceleration of the object’s motion? 0.5 m/s2 -0.5 m/s2 2 m/s2 -2 m/s2
Answer: -2m/s2
Explanation:
Using the following equation ; acceleration = Change in velocity / time
i.e a = v - u / t
where 'a' = acceleration
v = final velocity
u = initial velocity
t = time
Therefore; from the graph we have acceleration to be, 0 - 6m/s / 3s = -2m/s2
For Group 2A metals, which electron is the most difficult to remove? the second the first the third All the electrons are equally difficult to remove.
Answer:
the third
Explanation:
when you remove the first the nucleur attraction becomes greater pulling the other valence electron closer thus the more you remove the harder it gets because the pull from the nucleus increases.
There are various kind of elements that are present in periodic table. Some elements are harmful, some are radioactive, some are noble gases. Option C is correct option.
What is periodic table?Periodic table is a table in which we find elements with properties like metals, non metals, metalloids and radioactive element arranges in increasing atomic number.
The elements that belongs to Group 2A metals are alkaline earth metals, their electronic configurations is [noble gas ]ns² so, it is easy to remove first electron and then second electron but it is very difficult to remove the third electron because after removing two electron we get noble gas configuration and effective nuclear charge also increases after removal of second electron.
Therefore, the correct option is option C.
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What are some similarities and differences between group 1, 0 and 7 elements on the periodic table?
Answer:
Difference : group 1 elements are known as alkali metals, group 7 elements are known as transition metals
Similarities : Both group 1 and 7 elements become more reactive as u go down and up respectively
Which factor plays the biggest role in delaying the detection of childhood
diseases?
Answer:
poor access to health care providers
Explanation:
without health care providers you cant get tested.
endothermic or exothermic?
The reaction between ammonium nitrate and water absorbs heat from the surrounding environment.
Three drops of concentrated sulfuric acid added to 100 milliliters of water in a beaker makes the beaker hot.
Ammonium chloride dissolved in a beaker of water makes the beaker cold.
Uranium atoms are split to produce nuclear energy.
Water separates into hydrogen and oxygen when an electric current is run through it.
Methane and oxygen are combined to produce methanol and heat.
Answer:
Endothermic
Exothermic
Endothermic
Exothermic
Exothermic
Exothermic
Explanation:
Endothermic is when a reaction absorbs heat.
Exothermic is when a reaction releases heat.
Endothermic reactions:
The reaction between
ammonium nitrate and
water absorbs heat
from the surrounding
environment.
Ammonium chloride dissolved
in a beaker of water makes the
beaker cold.
Water separates into
hydrogen and oxygen
when an electric current
is run through it.
Exothermic reactions:
Three drops of concentrated
sulfuric acid added to 100
milliliters of water in a beaker
makes the beaker hot.
Uranium atoms are split to
produce nuclear energy.
Methane and oxygen are
combined to produce
methanol and heat.
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Other than carbon being relatively small, what is another reason that carbon can form so many compounds? the ability to form four covalent bonds the ability to change shape the ability to form a diatomic molecule the ability to split its electrons
Answer:
Ability to form four covalent bonds.
Explanation:
Carbon is the first member of group 14. It is essentially a nonmetal. It is a small atom which regularly exhibits tetra valency. This means that carbon is able to form four covalent bonds to four chemical species which may be the same or different each time. This leaves room for many different possible combination patterns of carbon with other chemical species.
Hence carbon forms a very large number of compounds due to its small size and its ability for form four covalent bonds to other chemical species in any bonding situation.
Answer: the ability to form four covalent bonds
Explanation:
Sulphuric acid, also called ‘king of chemicals' has the formula H2SO4. Its appearance is different from that of hydrogen and sulphur. Give two other reasons why sulphuric acid is a compound and not a mixture.
Explanation:
Before proceeding to answering the question, we have t understand what we mean by both mixture and compound.
A mixture is the physical combination of two or more substances in which the identities are retained and are mixed in the form of solutions, suspensions and colloids.
A compound on the other hand is a chemical substance composed of many identical molecules composed of atoms from more than one element held together by chemical bonds.
The two other reason why H2SO4 is a compound and not a mixture are;
1) The components which are Hydrogen, Sulphur and Oxygen cannot be separated by physical means.
2) It has a constant melting and boiling point.
The number of joules needed to raise the temperature of 32 g of water from 12 °C to 54 °C is
The specific heat of water is 4.184 J/g °C.
Answer: 5,600 J
Explanation:
Joules = mass x specific heat x temperature change
32 x 4.184 x (54 - 12)
= 133.888 x 42
= 5,623.296
(significant figures => 5,600)
(SOMEONE HELP!!! PLEASE) What are some similarities and differences between ionic and covalent bonds?
Answer:
Ionic and covalent bonds are different in many ways.
Explanation:
A covalent bond is where electrons are shared between several atoms and is apparent in H20 also known as water.
Ionic bonds occur when an atom "gives away" one of its electrons to another one, and due to this difference in charge, they are attracted to each other.
Here is a list of differences:
Ionic bonds are typically strongerCovalent bonds have atoms that are electrically neutral, while ionic bonds have electrically charged atomsCovalent bonds are far more common in nature than ionic bondsCovalent bonds from between two non metals, whereas ionic bonds are formed by a metal and a nonmetalIonic compounds are usually solid whereas Covalent compounds are usually liquid or gasCovalent bonds can form between two atoms of the same element, where this is not possible with ionic bonds.Here are some similarities:
Valence electrons are involved in both bonding processesThe result of both bonds is electrically neutral, even if each individual atom isn'tWhen atoms bond together, they release heat whether or not they are covalent or ionicBoth covalent and ionic bonds lead to stable compounds.Hope this helps!
What did the photoelectric experiment demonstrate?
A. Light can cause electrons to be released from the surface of a
metal.
B. Light can deposit electrons on a metal surface.
C. Light can make metal atoms move around, producing electricity.
D. Light can heat metal enough to produce electricity.
Explanation:
When an electromagnetic wave like light hits a material, the electrons gets emitted. The emission of electrons is called photoelectric effect. The emitted electrons are called photoelectrons. In this process the transfer of energy takes place from light to an electron.
Hence, the correct option regarding the photoelectric experiment is (A) " Light can cause electrons to be released from the surface of a metal."
A perfume bottle is dropped in the comer of a room. The odor of the perfume can be detected on the other side of the statement best describes this observation? Particles are moving from regions of high concentration to low concentration.Particles are moving from regions of low concentration to high concentration. Particles are moving through a small opening into a smaller volume. Particles are moving through a small opening into a larger volume.
Answer:
Particles are moving from regions of high concentration to low concentration.
hope this answer correct (^^)
Answer:
A. Particles are moving from regions of high concentration to low concentration.
Explanation:
took a test
How might a scientist confirm the results of other expirements by doing an experiment
Which substance is a mixture? Table salt, gasoline, aluminum, carbon dioxide?
Answer:
b.) gasoline
Explanation:
The rest mentioned are pure substances/compounds which is not a mixture.
A substance is said to be a mixture if they are not able to get dissolved completely in the solution. Gasoline is a mixture. Thus, option B is correct.
What are mixtures?Mixtures are the substances that are formed by mixing two or more compounds that have been not able to show any chemical bond and linkage. They are physical combinations rather than chemicals.
Gasoline is a homogeneous mixture that is formed by the combination of hydrocarbons and differs from other substances that are pure substances or compounds.
Table salt, aluminum, and carbon dioxide are pure substances that are formed of the same type of molecules or atoms. Table salt is made of Na and Cl atoms, aluminum is made of a single atom, and carbon dioxide of carbon and oxygen atom.
Therefore, gasoline is a mixture.
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differentiate between short period and long period
The question is incomplete. The complete question is as follows:
Differentiate between a short period and long period production functions.
Answer:
Difference between a short period and long period production functions is as follows:
Short period: During this period at least one of the factors of production is available in a fixed quantity. For example: Framers having fixed land for growing crops.
Long period: During this period all the factors of production are variable. So change in any variable can increase the production.
A compound ‘X’ is used for drinking, has pH =7.Its acidified solution undergoes decomposition in presence of electricity to produce gases ‘Y’ and ‘Z’ The volume of Y is double than Z. Y is highly combustible whereas Z is supporter of combustion. Identify X, Y & Z and write the chemical reactions involved.
Answer:
X = Water (H2O) ; Y = Hydrogen ; Z = Oxygen
Explanation:
2(H2O) -------> 2H2 + O2
Lawrence experienced a major accident in class. His entire test tube rack with all his chemicals fell and broke. There were chemicals all over the floor. Which would be used to clean his mess? eye wash safety shower sponge chemical spill kit
Answer:
The correct option is;
Chemical spill kit
Explanation:
When cleaning simple chemical spills that do not spread or indirectly put people and property in danger and does not negatively impact o the environment the risk, quantity and likely impact of the spill should be evaluated then with a chemical spill kit which comprises of personal protective clothing, materials that are absorbent, waste bags, broom and dustpan and a waste container can be used absorb, contain the residues, clean the spill and put the collected waste away.
Answer:
Chemical spill kit
Explanation:
uh yeah
determine the type of the following chemical reaction: Mg(s) + 2HCl(aq)——-> H2(g) + MgCl2(aq) a. single replacement reaction b. decomposition reaction c. combination reaction d. double replacement reaction
Answer:
a. single replacement reaction
Explanation:
Mg(s) + 2HCl(aq)——-> H2(g) + MgCl2(aq)
Mg replaces H, so this is a single replacement reaction.
2.70g of Zn (s) reacts with 50.0 mL of 1.00 M HCl solution to produce hydrogen gas according to the reaction. (R = 0.08206 L·atm·K-1·mol-1) Zn(s) + 2HCl (aq) = ZnCl2 (aq) + H2(g) a) calculate mole of Zn used in this reaction b) calculate mole of HCl used in this reaction c) calculate which reactant is a limiting reactant d) calculate mole of hydrogen gas formed e) calculate volume of H2 gas at STP in Liters that will be produced during the reaction
Answer:
a. 0.0413 moles Zn
b. 0.0500 moles HCl
c. HCl is the limiting reactant
d. 0.0250 moles H₂
e. V = 0.56L
Explanation:
The reaction of Zn(s) with HCl is:
Zn(s) + 2HCl (aq) → ZnCl₂ (aq) + H₂(g)
Where 1 mole of Zn reacts with 2 moles of HCl.
a) To convert mass in grams to moles of a substance you need to use molar mass (Molar mass Zn: 65.38g/mol), thus:
2.70g Zn × (1mol / 65.38g) = 0.0413moles of Zn
b. Now, when you have a solution in molarity (Moles / L), you can know the moles of a volume of solution, thus:
Moles HCl:
50.0mL = 0.0500L × (1.00mol / L) = 0.0500 moles HCl
c. The limiting reactant is founded by using the chemical reaction as follows:
For a complete reaction of 0.0500 moles HCl you need:
0.0500 moles HCl × (1 mole Zn / 2 moles HCl) = 0.0250 moles Zn
As you have 0.0413 moles of Zn, and you need just 0.0250 moles for the complete reaction, Zn is the exces reactant and HCl is the limiting reactant
d.As HCl is limiting reactant and 2 moles of HCl react with 1 mole of H₂, moles of hydrogen formed are:
0.0500 moles HCl × (1 mole H₂ / 2 moles HCl) = 0.0250 moles H₂
e. Using PV = nRT, you can find volume of gas, thus:
PV = nRT
V = nRT / P
Where P is pressure 1atm at STP, n are moles, R is gas consant 0.08206Latm/molK and T is absolute temperature 273.15K at STP.
V = 0.0250molesₓ0.082atmL/molKₓ273.15K / 1atm
V = 0.56L
3 point different between fundamental units and derived units
Answer:
Fundamental Units:
1) Fundamental units also called base units are used to describe base quantities
2) They cannot be expressed in terms of derived units.
3) Examples : Meter, Ampere, Second etc.
Derived Units:
1) Derived units are used to describe derived quantities.
2) They can be expressed in terms of fundamental units.
3) Examples: Newton, Joule, Hertz, Pascal etc.
Answer:
3diferences
Explanation:
fundamental are independent but derived are dependent
there are 7fundamental units but there are many derived units from fundamental.
meter, second, kilogram, etc are examples of fundamental but m/s^2, newton, joule, etc are derived units
Why is making proteins important
A welding torch produces a flame by burning acetylene fuel in the presence of oxygen. This flame is used to melt a metal. Which energy transformation represents this process?
chemical energy into thermal energy
kinetic energy into potential energy
kinetic energy into electromagnetic energy
potential energy into chemical energy
Answer:
chemical energy into thermal energy
Explanation:
The reaction taking place is as follows
2C₂H₂ + 5O₂ = 4CO₂ + 2H₂O + Heat
In this reaction bonds present in acetylene is broken and new bond present in water and carbon dioxide are formed . In the whole process of bond breaking and bond formation , there is net loss of energy and that energy is released as heat energy .
Thus we can say that in the whole process , chemical energy is converted into heat energy .
Answer:
A: chemical energy into thermal energy.
Explanation:
PLEASE HELP!! thank you Which element does X represent?
Answer:
95 Kr36
Explanation:
The process by which a large nucleus split into two smaller nuclei is called nuclear fission and occurs after the nucleus has absorbed a neutron that is a product of the radioactive decay of another atom. The formed fission fragments are unstable and extremely radioactive.
Explain the methods of passive transport that move molecules across the plasma membrane of the cell.