Answer: The difference between a physical reaction and a chemical reaction is composition. In a chemical reaction, there is a change in the composition of the substances in question; in a physical change there is a difference in the appearance, smell, or simple display of a sample of matter without a change in composition.
Explanation:
2.
In photosynthesis, which substances are used up, which are produced and which are necessary
but remain unchanged after the reaction?
used up
produced
remain
A
carbon dioxide
water
oxygen
A
8
chlorophylt
carbon dioxide
water
с
oxygen
starch
cellulose
D
water
oxygen
chlorophyll
D. Water is used up, Oxygen is produced and Chlorophyll is necessary, but remains unchanged.
Any individual offspring produced through a sexual reproduction is always,
Answer:
Any individual offspring produced through asexual reproduction is always: genetically identical to its parent. made up of cells with a cell wall. different from all of its siblings
why is unit of pressure called a derived unit ?? 2) how do you measure the volume of milk?
1. Unit of pressure called a derived unit because it is a combination of base units (kg·m^-1·s^·2).
2. We measure the volume of milk by a instrument called Milk Lactometer.
The presence of which gas makes the planets Uranus and Neptune appear blue?
a. helium
b. hydrogen
c. methane
d. nitrogen
Answer:
C. METHANE
Explanation:
The blue color of both the ice giants can be contributed to the presence of methane in their upper atmospheres. Methane absorbs most of the red light incident on the planets which makes them appear blue in color.
Mercury poisoning is a debilitating disease that is often fatal. In the human body, mercury reacts with essential enzymes leading to irreversible inactivity of these enzymes. If the amount of mercury in a polluted lake is 0.4 Hg/mL, what is the total mass in kilograms of mercury in the lake
Answer:
The total mass of mercury in the lake is 631,542.7 kg
Explanation:
Question: The given dimensions of the lake as obtained from a similar question posted online are;
The surface area of the lake, A = 100 mi²
The lake's average depth, d = 20 ft.
The concentration of the mercury, C = 0.4 μg Hg/mL = 0.4 × 10⁻⁶ kg Hg/L
Therefore, we have;
The volume of water mixture in the lake, V = A × d
∴ V = 100 mi² × 20 ft. = 2,787,840,000 ft.² × 20 ft. = 55,756,800,000 ft.³
1 ft³ = 28.31685 L
∴ 55,756,800,000 ft.³ = 55,756,800,000 ft.³ × 28.31685 L/ft.³ = 1.57885675 × 10¹² L
The total mass of mercury in the lake, m = C × V
∴ m = 0.4 × 10⁻⁶ kg Hg/L × 1.57885675 × 10¹² L = 631,542.7 kg
The total mass of mercury in the lake, m = 631,542.7 kg.
e) Hydrogen gas is a non-metal and can be prepared in a laboratory Explain why hydrogen gas is collected over water.
Answer:
to collect pure hydrogen and avoid mixing with air
El hipoclorito de sodio (NaClO), es vendido en una solución clara de ligero color verde-amarillento y un olor característico que se conoce con el nombre genérico Límpido, con una concentración del 6%. Pero para la desinfección de superficies el Límpido, debe ser diluido al 0,5%. Cuánto Límpido debemos sacar del recipiente para obtener 200 ml de una solución al 0,5%.
Respuesta:
16,7 mL
Explicación:
Paso 1: Información provista
Concentración inicial (C₁): 6%Volumen inicial (V₁): ?Concentración final (C₂): 0,5%Volumen final (V₂): 200 mLPaso 2: Calcular el volumen de la solución concentrada
Queremos preparar una solución diluida de hipoclorito de sodio a partir de una concentrada. Podemos calcular el volumen inicial que debemos tomar usando la regla de dilución.
C₁ × V₁ = C₂ × V₂
V₁ = C₂ × V₂ / C₁
V₁ = 0,5% × 200 mL / 6% = 16,7 mL
How many moles of air are in a hot- air balloon with a volume of 2200m ^ 3 at a temperature of 388 K and a pressure of 100 kPa?
Answer:
Number of moles, n = 68.20 moles
Explanation:
Given the following data;
Volume, V = 2200 m³Temperature, T = 388 KPressure, P = 100 kPaIdeal gas constant, R = 8.314 J/mol·K or 0.08206 L·atm·mol−1·K−1To find the number of moles, we would use the ideal gas law equation;
PV = nRT
Where;
P is the pressure.V is the volume.n is the number of moles of substance.R is the ideal gas constant.T is the temperature.Making n the subject of formula, we have;
[tex] n = \frac {PV}{RT} [/tex]
Substituting into the formula, we have;
[tex] n = \frac {100 * 2200}{8.314 * 388} [/tex]
[tex] n = \frac {220000}{3225.832} [/tex]
Number of moles, n = 68.20 moles
What is the atomic number of the atom in the diagram above please ?
Answer:
5
Explanation:
The atomic number is the number of protons in an atom. Protons are the positively charged particles in the nucleus. The number of protons define the identity of an element. An element with 5 protons is Boron, no matter how many neutrons may be present.
The atomic number of the atom shown in the diagram is 5.
What is the atomic number?The atomic number of an element refers to the number of protons in the nucleus of its atoms. It uniquely identifies an element and determines its chemical properties.
In the diagram, there are 5 proton numbers in the nucleus of the atom. In other words, this means that the atomic number of the atom is 5.
More on atomic numbers can be found here: https://brainly.com/question/14190064
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Plz help I will give brainliest
Answer:
1. Fr
2. cl
3.H20
4.2 mole
5. 3
6. c
True or false, The four units that must always be used when using the ideal gas are 44.0 liters
Answer:
for volume only liters can be used
Explanation:
Elements in the same period Question 7 options: A) form bonds with the same type of elements. B) have the same number of protons. C) have the same number of valence electrons. D) have the same principal quantum number.
D is the answer .. I have send u pic also
balanced chemical equation:Copper( ii) oxide solid +dilute sulphuric acid
Answer:
CuO + H2SO4 = CuSO4 + H2O
Reaction type: double replacement
A 100 g sample of potassium chlorate, KCIO3(s), is completely decomposed by heating:
2 KCIO3(s) 2 KCl(s) + 3 O2(g)
The oxygen is collected at 89 kPa and 23°C. Calculate the volume, in litres, of oxygen that would be
produced during the decomposition of this sample.
Write a balanced molecular equation describing each of the following chemical reactions.
(a) Solid calcium carbonate is heated and decomposes to solid calcium oxide and carbon
dioxide gas.
(b) Water vapor
Answer:
don't know..............
An example of basic research is A) the development of new plastics that can be recycled. B) the study of the relationship between the amount of automobile emissions gases in the atmosphere and the decomposition of atmospheric ozone. C) the study of the composition of the atom. D) the design of new batteries for electric cars. E) the study of natural compounds in sea animals to look for new molecules that can be used for medicine.
Answer:
C) the study of the composition of the atom.
Explanation:
A research can be defined as a systematic investigation or careful consideration of study with respect to a particular problem using scientific methods such as collection of data, documenting critical information, analysis of data, and the establishment of facts in order to reach new conclusions.
Similarly, a basic research is an approach to research that's typically theoritical and it's aimed at developing a theory, searching for the truth or gain a better understanding about a phenomenon, subject, or basic laws on nature.
In this context, an example of basic research is the study of the composition of the atom.
An atom can be defined as the smallest unit comprising of matter that forms all chemical elements. Thus, atoms are basically the building blocks of matters and as such determines or defines the structure of a chemical element.
Generally, atoms are typically made up of three distinct particles and these are protons, neutrons and electrons.
Under certain conditions, the substance mercury(II) oxide can be broken down to form mercury and oxygen. If 24.1 grams of mercury(II) oxide react to form 22.3 grams of mercury, how many grams of oxygen must simultaneously be formed? Grams oxygen
Answer:
1.76 g
Explanation:
2HgO(s) ==> 2Hg(l) + O2(g)
Number of moles of Hg = 22.3 g/ 201g/mol
= 0.11 moles
From the reaction equation;
2 moles of Hg is formed alongside 1 mole of oxygen
Hence;
0.11 moles of Hg forms 0.11 moles × 1/2
= 0.055 moles of oxygen
Mass of oxygen formed = 0.055 moles of oxygen × 32g/mol = 1.76 g
what is the reactant(s) in the chemical equation below
3CO(g) + Fe2O3(s) 2Fe(s) + 3CO2(g)
Answer:
the reactants are carbon dioxide ,iron, oxygen
The first atmosphere a. consisted mainly of water, carbon dioxide, carbon monoxide, and methane. b. was replaced by a secondary atmosphere that, arguably, consisted partially of gases brought to the Earth by comets. c. was replaced by a secondary atmosphere only after the Earth developed gravity, which helped deflect the solar wind. d. dissolved into the Earth's oceans before it was replaced by a second atmosphere.
Answer:
Hence the correct option is option b - was replaced by a secondary atmosphere that, arguably, consisted partially of gases brought to the Earth by comets.
Explanation:
The first atmosphere was formed during the formation of the world.
But the secondary atmosphere formed mainly 2. billion years ago by earth's internal volcanic activity, or by the buildup of fabric from comet impacts.
Color of the CuCl2 hydrate before heating:
hydrated cucl2 have blue-green colour
A sample of gas occupies 1.2 L at 12.0oC. Assuming pressure remains the same, what would be the volume (in L) of this gas at 67oC?
A.
1.4
B.
1.0
C.
0.2
D.
5.0
E.
6.7
Answer:
e.
6.7
hope it help
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What amount of SeC16 is needed to produce 4.45 mol of chlorine gas in the
reaction Seclo +0 218) —SeO, +3Cl2te)?
2.85 mol
0.95 mol
5.70 mol
8.55 mol
1.49 mol
Answer:
1.48 moles of SeCl6 are needed
Explanation:
Based on the reaction:
SeCl6 + O2 → SeO2 + 3Cl2
1 mole of SeCl6 reacts producing 3 moles of Cl2.
To solve this question we need to use the conversion factor:
1mol SeCl6 = 3mol Cl2
As we want to produce 4.45 moles of Cl2, we need:
4.45 mol Cl2 * (1mol SeCl6 / 3mol Cl2) =
1.48 moles of SeCl6 are neededWhich 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)
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.
PLZ HELP ME WITH MY WORK
How many different elements are there in the molecule C8H11NO2,?
A. 21
B. 2
c. 11
D. 4
Answer:
option C 11
is the correct answer
The dehydration of a secondary alcohol, like cyclohexanol, is a mechanism that occurs Choose... . First, the alcohol is protonated to Choose... , creating Choose... intermediate. Then, a Choose... is removed, moving the electrons from that bond to make a Choose... bond.
Answer:
Mechanism
explanation:
have a great day!
By which process aqua fortis is manufactured
1) Haber's process
2) Ostwald process
3) Contact process
4) Deacon's process
Answer: Aqua fortis is also known as Nitric Acid
Explanation: and the process in making aqua fortis is THE OSTWALDS PROCESS
detailed explanation by me
ammonia is also used in this process, which is reacted with oxygen and water and a catalyst platinum.
HOPE THIS HELPSS!!!
A cylinder container with a diameter of 23.0 cm and a height of 140 cm contains N2O at a pressure of 108 kpa and temperature of 294 K. How many grams of N2O gas are in the cylinder?
Answer:
113.17 g
Explanation:
This can be solved using the Ideal Gas Equation:
PV=nRT
First step is to calculate the volume of the cylinder in L:
V=πr²h
V= π (11.5)² (140)
V= π (132.25) (140)
V = π (18.515)
V = 58,166.588 cm³ = 58.2 L
Then, convert kpa into atm:
1 kpa = 0.00987 atm
108 kpa = 1.06588 atm
Then, plug all of your values into the Ideal Gas Equation to solve for moles:
(1.06588)(58.2)=n(0.082057)(294)
62.034=n(24.125)
2.571357513=n
Finally, convert the moles into grams
2N = 28.0134 amu
O = 15.999 amu
_______________
44.0124 amu
(2.571357513moles)(44.0124 amu) = 113.17 g
The number of grams of helium in a balloon at a pressure of 99.8 kPa, a temperature of 301 K, and a volume of 0.785 L would be
Options:
814 g
0.125 g
0.278 g
337 g
The number of grams of helium in a balloon at a pressure of 99.8 kPa, a temperature of 301 K, and a volume of 0.785 L would be 0.125g.
How to calculate mass?The mass of a substance can be calculated by multiplying the number of moles by its molar mass.
However, the number of moles of helium must be calculated as follows:
PV = nRT
Where;
P = pressureV = volumen = no of molesR = gas law constantT = temperature0.985 × 0.785 = n × 0.0821 × 301
0.773 = 24.7n
n = 0.773 ÷ 24.7 = 0.031moles
mass of He = 0.031 × 4 = 0.125g
Therefore, the number of grams of helium in a balloon at a pressure of 99.8 kPa, a temperature of 301 K, and a volume of 0.785 L would be 0.125g.
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Name 2 materials that will ferment when added to water and mixed together at about 20°c.
Answer:
vegetables and salt
Explanation:
The ideal temperature for fermenting vegetables is between 18⁰-22⁰C. Within this range, the bacteria do their best work, giving high levels of lactic acid. The naturally occurring bacteria on fruits and vegetables is called lactobacillus. These bacteria convert the sugar to lactic acid, which is what gives that characteristic tangy/sour taste.
Calculate K for 2CO2(g) ⇔ 2CO(g) + O2(g)
given that the equilibrium concentrations of carbon monoxide, oxygen and carbon dioxide are 2.0 x 10-6 M, 1.0 x 10-6 M, and 0.25 M respectively.
Explanation:
here's the answer to your question
