Answer:
a. phisical change
Explanation:
Answer:
A
Explanation:
If a sample of air in a closed container was heated, would the total pressure of the air in the container increase, decrease, or remain unchanged? Explain your reasoning
Answer: Stay the same
Explanation:
Boyle's law is one of the fundamental gas laws, that describes the state of an ideal gas at a constant temperature. It states that the volume of a gas is inversely proportional to the external pressure applied at a constant temperature.
If a sample of air in a closed container was heated, the total pressure of the air would increase.
Let's suppose we have a sample of air in a closed container. We heat the container and we want to predict what would happen to the pressure.
According to Gay-Lussac's law, the pressure of a gas is directly proportional to its absolute temperature.
[tex]P \propto T[/tex]
Thus, if we increased the temperature of the air by heating it, its pressure would increase.
If a sample of air in a closed container was heated, the total pressure of the air would increase.
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True or false
The weighted average of the mass numbers of all the isotopes that
occur in nature for a particular element is the average atomic number.
Answer: false
Explanation: atomic mass
How many grams of neutral salt will be obtained in the reaction of calcium oxide with 200 cm 3 of phosphoric acid solution whose concentration is 0.3 mol / dm 3
Answer:
9.3 g of Ca3(PO4)2
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
3CaO + 2H3PO4 —> Ca3(PO4)2 + 3H2O
Next, we shall determine the number of mole of H3PO4 present in 200 cm³ of 0.3 mol/dm³ phosphoric acid (H3PO4) solution. This can be obtained as follow:
Molarity of H3PO4 = 0.3 mol/dm³
Volume = 200 cm³ = 200 cm³/1000 = 0.2 dm³
Mole of H3PO4 =?
Molarity = mole /Volume
0.3 = mole of H3PO4 /0.2
Cross multiply
Mole of H3PO4 = 0.3 × 0.2
Mole of H3PO4 = 0.06 mole
Next, we shall determine the number of mole of the salt, Ca3(PO4)2, obtained from the reaction. This can be obtained as shown below:
3CaO + 2H3PO4 —> Ca3(PO4)2 + 3H2O
From the balanced equation above,
2 moles of H3PO4 reacted to produced 1 mole of Ca3(PO4)2.
Therefore, 0.06 moles of H3PO4 will react to produce = (0.06 × 1)/2 = 0.03 mole of Ca3(PO4)2.
Thus, 0.03 mole of Ca3(PO4)2 is produced from the reaction.
Finally, we shall determine the mass of Ca3(PO4)2 produced as follow:
Mole of Ca3(PO4)2 = 0.03 mole
Molar mass of Ca3(PO4)2 = (40×3) + 2[31 + (16×4)]
= 120 + 2[31 + 64]
= 120 + 2[95]
= 120 + 190
= 310 g/mol
Mass of Ca3(PO4)2 =?
Mole = mass /Molar mass
0.03 = mass of Ca3(PO4)2 / 310
Cross multiply
Mass of Ca3(PO4)2 = 0.03 × 310
Mass of Ca3(PO4)2 = 9.3 g
Thus, 9.3 g of Ca3(PO4)2 was obtained from the reaction.
first correct will get brainliest
Answer:
? I am confused. What is the question?
Explanation:
analysis definition?
Explain how the tasks an organism completes will influence their cellular respiration levels.
Answer:
All living things use cellular respiration to turn organic molecules into energy. ... This process makes energy from food molecules available for the organism to carry out life processes. Cellular respiration usually occurs in the presence of oxygen. This is called aerobic respiration.
Metallic substances will conduct electricity in A) the liquid phase, only B) neither the solid nor the liquid phase C) the solid phase, only D) both the solid and the liquid phase
Answer:
D) both the solid and the liquid phase
Explanation:
Metallic substances will conduct electricity in both the solid and liquid phase. Metals are generally conductors of heat and electricity.
In metals there are free mobile electrons the enables the flow electricity. The free mobile electrons is utilized by the metals to conduct electricity. Metals generally have metallic bonds that holds their particles together. The metallic bonds enables metals to have a sea of delocalized electrons. Metals have a large atomic radius and larger electron pool.when the subscript is present it is implies to which element
Answer: The element in front of the subscript is what it applies to!
Explanation:
1) What is bioluminescence?
The double replacement reaction between calcium nitrate (Ca(NO3)2) and potassium oxide (K2O ) is shown below:
Ca(NO3) 2 + K2 O → CaO + KNO3
How many grams of potassium oxide would be needed to produce 5.00 g of potassium nitrate (KNO3) ?
Answer:
Mass = 2.355 g
Explanation:
Given data:
Mass of K₂O needed = ?
Mass of KNO₃ produced = 5.00 g
Solution:
Chemical equation:
K₂O + Ca(NO₃)₂ → CaO + 2KNO₃
Number of moles of KNO₃:
Number of moles = mass/molar mass
Number of moles = 5.00 g/ 101.1 g/mol
Number of moles = 0.05 mol
now we will compare the moles of KNO₃ and K₂O.
KNO₃ : K₂O
2 : 1
0.05 : 1/2×0.05 = 0.025 mol
Mass of potassium oxide needed in gram:
Mass = number of moles × molar mass
Mass = 0.025 mol × 94.2 g/mol
Mass = 2.355 g
Water sticks well to many different materials. What term relates to this property of water?
A. adhesion
B. cohesion
C. density
D. surface tension
Answer:
A. Adhesion
Explanation:
The prefix ad- means "to, toward". Most terms like that describe something connect to another.
Answer:
B. Cohesion
Explanation:
A water drop is composed of water molecules that like to stick together-an example of the property of cohesion
What is the Bayer process explain it
Answer:
The Bayer process is the principal industrial means of refining bauxite to produce alumina (aluminium oxide) and was developed by Carl Josef Bayer. Bauxite, the most important ore of aluminium, contains only 30–60% aluminium oxide (Al2O3), the rest being a mixture of silica, various iron oxides, and titanium dioxide.
What is the kinetic energy of a 25 kg object moving at a velocity of 2.5 m/s?
Answer:
78.13 JExplanation:
The kinetic energy of an object can be found by using the formula
[tex]k = \frac{1}{2} m {v}^{2} \\ [/tex]
m is the mass
v is the velocity
From the question we have
[tex]k = \frac{1}{2} \times 25 \times {2.5}^{2} \\ = 12.5 \times 6.25 \\ = 78.125 \: \: \: \: \: \: \: \: [/tex]
We have the final answer as
78.13 JHope this helps you
examples of a pure substances
Answer:
Explanation:
Examples of pure substances include tin, sulfur, diamond, water, pure sugar (sucrose), table salt (sodium chloride) and baking soda (sodium bicarbonate). Crystals, in general, are pure substances. Tin, sulfur, and diamond are examples of pure substances that are chemical elements.
Answer:
Examples of pure substances include tin, sulfur, diamond, water, pure sugar (sucrose), table salt (sodium chloride) and baking soda (sodium bicarbonate). Crystals, in general, are pure substances. Tin, sulfur, and diamond are examples of pure substances that are chemical elements
Explanation:
An engineer thinks that changing the catalyst used in a chemical reaction will
increase the rate of the reaction. This is an example of which step in the
engineering process?
A. Manufacture and test a prototype.
B. Identify solutions to the problem.
C. Plan a detailed design.
D. Research the problem.
Answer:
B. Identify solutions to the problem.
Explanation:
In the case described above, the engineer has already designed and attempted to manufacture a prototype for the process. The design of the process must have also been carefully researched and planed.
However, he identified the problem of low yield and is now working towards identifying solutions to the problem. One option he seeks to explore according to the question is to change the catalyst used in the reaction.
Aspirin , C9H8O4 , is the active ingredient in many prescription pain relievers. Its molar mass is 148 g/mol. a. If the tablets in a bottle contain a total of 38g of Ibuprofen , how many moles of aspirin are in the bottle? b. How many molecules of aspirin are in the bottle? c. What is the total mass in grams of carbon in 38g of aspirin?
Answer:
. (3 pts each) Carry out the following operations, and express the answer with the appropriate number of significant figures:
a. 1.24056 + 75.8 =
1.24056
+75.8
77.04056 -> Round to tenths place: 77.0
b. 320.55 – (6104.5/2.3) =
320.55
-2654.1304
-2333.580 -> round to HUNDREDS place: -2300 or -2.3 x 103
c. (0.0045 x 20,000.0) + (2813 x 12) =
90.000
+33756.000
33846.000 -> round to TEN THOUSANDS place: 34000 or 3.4 x 104
The all-time record lowest temperature ever recorded on this planet is –57.63 oC (recorded on July 21, 1983 in Vostok, the Russian Antarctic station).
a. Express this temperature in oF.
oF = (9/5)oC + 32
= (9/5)(-57.63) + 32 = -71.734 oF à -71.73 oF
b. Express this temperature in Kelvins (K).
K = oC + 273.15
= -57.63 + 273.15 = 215.52 K à 215.52 K
3. (10 pts) A 26.27-g sample of a solid is placed in a flask. Toluene, in which the solid is insoluble, is added to the flask so that the volume of the solid and liquid together is 50.00 mL. The solid and liquid toluene together weigh 52.65 g. The density of toluene at the temperature of the experiment is 0.864 g/mL. What is the density of the solid?
solid + toluene = 52.65 g
solid = 26.27 g
Mass of toluene = 26.38 g toluene
26.38 g toluene x 1 ml toluene = 30.53241 mL toluene
0.864 g toluene
solid + toluene = 50.00 mL
toluene = 30.53241 mL
solid = 19.46759 mL
density of the solid = 26.27 g
19.46759 mL
= 1.34942 g/mL à 1.35 g/mL
4. (16 pts) Fill in the gaps in the following table:
Symbol
52Cr3+
107Ag+
75As3-
Protons
24
47
33
Neutrons
28
60
42
Electrons
21
46
36
Net Charge
3+
1+
3-
. (2 pts each) From this list of elements: Ar, H, Ga, Al, Ca, Br, Ge, K, O; pick the one that best fits each of the following descriptions. You may use each element only ONCE.
a. an alkali metal: K
b. an alkaline earth metal: Ca
c. a noble gas: Ar
d. a halogen: Br
e. a metalloid: Ge
f. a nonmetal listed in group IA: H
g. a metal that forms a 3+ ion: Al
h. a nonmetal that forms a 2- ion: O
i. an element that resembles aluminum: Ga
6. (1 pt each) Give the atomic symbol for the following elements:
a. calcium: Ca
b. sodium: Na
c. mercury: Hg
d. lead: Pb
3 pts each) Write a complete, balanced chemical equation for each of the following reactions:
a. Solid calcium carbide (CaC2) reacts with water to form an aqueous solution of calcium hydroxide and acetylene gas (C2H2).
HOPE THIS HELPS YOU OUT :3
*40 IF YOU ANSWER CORRECTLY & ADDED BRAINIEST*
*IF COMMENT IS IRRELVANT, YOUR ACCOUNT WILL BE REPORTED*
1.) An electron configuration of 2-7-6 represents the atom of...
A.) phosphorus and is in the ground state
B.) phosphorus and is in the excited state
C.) potassium and is in the ground state
D.) potassium and is in the excited state
2.) An atom contains three valence electrons. This atom could be
A.) sodium
B.) magnesium
C.) aluminum
D.) silicon
Answer:
1. B
2. C
Explanation:
1. There are 15 electrons which means that the element is phosphorus. We know it is in the excited state because an electron from the second ring has moved to the third one, typically it would be 2 - 8 - 5.
2. An element with 3 valence electrons will be 3 spaces from the left side of the periodic table. Sodium is 1, Magnesium is 2, Aluminium is 3, and Silicon is 4. Noble gasses on the right have all 8.
The diagram shows the different models of the atom that eventually led to the modern atomic theory. Four diagrams are shown labeled Model A, Model B, Model C, Model D from left to right. The diagram labeled Model A has a small sphere with a positive sign on it. This small sphere at the center is surrounded by a shaded circle. The shaded circle has negative signs placed randomly inside it. The diagram labeled Model B is a large solid sphere. The diagram labeled Model C has a sphere at the center and a dotted cloud around the sphere. The dotted cloud is dense near the sphere and becomes faint as we move away from the sphere. The diagram labeled Model D has a sphere surrounded by three concentric circles. Each concentric circle has some spheres on it. Which model is based on Bohr's quantum model?
Answer:
the answer is B i just took the test on edge <3
Explanation:
because it do what it do
Answer:
The Answer is A on Edge 2021
Explanation:
I took the unit test exam and got a 100%
Soaps feel slippery on our hands because they dissolve the oil on our skin, decreasing friction.This is because soap contains a neutral molecule. a salt molecule. an acid. a base.
Answer:
D- a base
Explanation:
edge 2021
Soap has the base properties in its composition that make it slip on the hand.
What is the chemical composition of soap?The most commonly used are sodium hydroxide (NaOH), potassium hydroxide (KOH) and sodium carbonate (Na2CO3). All are solid and white in color. Additives: in general, these are the products that provide the soap's fragrances and coloring.
They are chemical compounds (lipids) originated from the reaction between glycerol (alcohol) and saturated or unsaturated fatty acids, which have long chains, containing a carboxyl group at one end.
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4. Classify as man-made or natural extinction: Volcanic Eruptions
O Both
O Natural Extinction
O Man-made
O Neither
Answer:
2nd one
Explanation:
What percentage of the earth's surface is covered by marine habitats?
Answer: 70 percent
About 97 percent of Earth's water is in the ocean.
The ocean covers more than 70 percent of the surface of our planet. It's hard to imagine, but about 97 percent of the Earth's water can be found in our ocean. Of the tiny percentage that's not in the ocean, about two percent is frozen up in glaciers and ice caps.
Hope this helps...... Stay safe and have a Merry Christmas!!!!!!!!!!! :D
Explanation:
The density of mineral oil is 0.835 g/mL. what is the mass in grams of a sample of mineral oil that has a volume of 3.50 mL.
Answer:
2.92 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volume
From the question we have
mass = 0.835 × 3.50 = 2.9225
We have the final answer as
2.92 gHope this helps you
When Is Mechanical Energy Not Conserved?
Question 1 options:
when there is significant friction or air resistance or other force affecting on the object.
when it is cold outside
when you are in outer space
when the electricity is turned off
HURRY GIVE POINTS
Answer:
i think d
Explanation:
For the reaction: 4Fe+3O2= 2Fe2O3 if 100g of Fe are used how much of O2 is used
Answer:
Mass = 42.88 g
Explanation:
Given data:
Mass of iron = 100 g
Mass of O₂ = ?
Solution:
Chemical equation:
4Fe + 3O₂ → 2Fe₂O₃
Number of moles of Iron:
Number of moles = mass/molar mass
Number of moles = 100 g/ 55.85 g/mol
Number of moles = 1.79 mol
Now we will compare the moles iron with oxygen.
Fe : O₂
4 : 3
1.79 : 3/4×1.79 = 1.34 mol
Mass of oxygen used:
Mass = number of moles × molar mass
Mass = 1.34 mol × 32 g/mol
Mass = 42.88 g
gamma rays have an approximate wavelength of 1.0x10^-13 meters. what is the approximate energy of a gamma-ray?
Answer:
E = 19.89 × 10⁻¹³ J
Explanation:
Given data:
Wavelength of gamma ray= 1.0× 10⁻¹³ m
Energy of gamma ray = ?
Solution:
Formula:
E = h c/λ
h = plancks constant = 6.63× 10⁻³⁴ js
c = speed of light = 3 ×10⁸ m/s
by putting values,
E = 6.63× 10⁻³⁴ js × 3 ×10⁸ m/s /1.0× 10⁻¹³ m
E = 19.89 × 10⁻²⁶ J.m/ 1.0× 10⁻¹³ m
E = 19.89 × 10⁻¹³ J
957 8339 9168 I’d
972205 passcode
Chemistry class
Answer:okay
Explanation:
A force of 20N acts on an object. It causes a displacement of 500 cm in the direction of force. What would be the work done in Nm on the object?
Answer:
500/100=5m
W=F*D
W=20*5=100Nm
Explanation:
The work done in Nm on the object is 100 Nm
Calculation of the work done:
Since A force of 20N acts on an object. It causes a displacement of 500 cm in the direction of the force.
Since the displacement is in cm
So, in meters, it should be like
= 500 / 100
= 5 m
Now we know that
Work done = force * displacement
= 20N * 5
= 100 Nm
hence, The work done in Nm on the object is 100 Nm
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Where is the change in the electron configuration for Na when in an
excited state? *
W
O A change in the last shell
O A change in the second and third shell
O A change in the first second and third
O No change at all
Answer: A change in the first second and third
Explanation:
An electron in the lowest energy state is called as ground state and is also known as stable energy level. An electron in the upper energy state is called as excited state and is also known as unstable energy level.
Electronic configuration represents the total number of electrons that a neutral element contains. The electrons are filled according to Afbau's rule in order of increasing energies. As the atomic number of sodium is 11. The electronic configuration of sodium will be represented in ground state as:
[tex]Na:11:1s^22s^22p^63s^1[/tex]
Thus any electron if occupies a higher shell, the atom is said to be in excited state.
Oxygen and sugar is transported to cells by the what system
1. Excretory system
2. Nervous system
3. Circulatory system
Answer:
the circulatory system
write an essay on the importance of our cultural heritage
Answer:
write the essay
Explanation:
