A mystery element has 18 protons. Which one of the following statements is true about the element?
o
A. The element belongs in row 2 of the periodic table and is classified as a halogen.
O
B. The element belongs in row 3 of the periodic table and is classified as a noble gas.
O
C. The element belongs in row 4 of the periodic table and is classified as an alkali metal.
D. The element belongs in row 5 of the periodic table and is classified as an alkaline earth metal.
Answer:
B
Explanation:
Elements in a group are determined by the number of valence electrons
Elements in a period are determined by the number of electrons shell
The electronic configuration of the element is
2,8,8
the number of valence electron is 8 that means it is in Group 8/O
the number of electron shell is 3 that means it is in period (row) 3
Group 8/O elements are called Noble gases
Why glucose does not give positive result with iodine test but not starch?
Answer:
This is a physical test. A chemical test for starch is to add iodine solution (yellow/brown) and look for a colour change. In the presence of starch, iodine turns a blue/black colour. ... Benedict's reagent will give a positive test result for glucose but not for starch.
Explanation:
please give me brainlist and follow
Answer:Amylose in starch is responsible for the formation of a deep blue color in the presence of iodine. The iodine molecule slips inside of the amylose coil.
Explanation:This makes a linear triiodide ion complex with is soluble that slips into the coil of the starch causing an intense blue-black colo
what does an electromagnet create?
a. electricity
b. magnet
c. neutrons
Answer:
Electromagnet creates electricity.
Explanation:
Which is not a way to accelerate an object ? Speed it up slow it down change its direction apply balanced forces
Answer:
Objects are NOT accelerating if they are traveling in a straight line at constant speed
Slow it down
Chlorination of phenol gives para product but bromination of phenol gives Ortho para product why
Answer:
here you go
Explanation:
The reaction of phenol with bromine is known as bromination of phenol. Solvent has great influence on the reaction. In different solvents, different products are obtained. The action of bromine on phenol can be explained as:
Reaction with bromine in water:—-
Reaction with bromine in water
Phenol reacts with bromine water to give 2,4,6-tribromophenol.
In water, ionisation is facilitated. Phenol gets ionised to form phenoxide ion, which is even better ortho,para-directing. Bromine also gets ionised to a larger extent to form a large number of bromonium ions. And Bromine ions are highly stabilized in ionic solvents. So the formation of strong o,p-directing group and stabilization of Br+ enhances the formation of tribromophenol.
Reaction with bromine in CS2:—-
Reaction with bromine in non-polar organic solvents
Phenol reacts with bromine in a presence of Carbon disulphide to form a mixture of o-bromophenol and p-bromophenol. Among which p-bromophenol predominates. In CS2 ionisation is not facilitated that much. As it is a non-polar solvent it doesn't the Br+ on. Also −OH group is moderately o,p-directing. So as usual para-product is more formed.
What 3 parts of the water cycle are a result of gravity?
Answer:
Hey mate.....
Explanation:
This is ur answer......
While sunlight is the energy source, the greatest force propelling the water cycle is gravity. Gravity is the force of attraction between two objects, and Earth's gravity pulls matter downward, toward its center. It pulls precipitation down from clouds and pulls water downhill. Gravity also moves air and ocean water.
Hope it helps!
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What is the difference between global warming and climate change? *
1 point
There is no difference, we can use either term
Climate change happens because of humans, global warming happens naturally
Global warming focuses only on temperature increases, climate change only focuses on temperature decreases
Global warming focuses only on temperature increasing, climate changes is a broader term that refers to the range of changes happening on Earth in addition to temperature changes
Answer: D: Global warming focuses only on temperature increasing, climate changes is a broader term that refers to the range of changes happening on Earth in addition to temperature changes
Explanation:
Answer:
what he/she said
Explanation:
How do I solve this? please help and only respond with the answer/work. I will mark BRAINLIEST
Calculate the molarity of a substance that is 10 mol in a 4L solution.
0.25 M
2.5 M
40 M
63.6 M
Answer: I think the answer is 2.5 M.
Explanation: Formula: M = n/v
M= 10 mol / 4L
M= 2.5 M
Cu is in FCC structure. We know that even at close to melting temperature, vacancies are still sparsely distributed, i.e., it is almost impossible to find two vacancies directly adjacent to each other. So, for a single vacancy (assuming that it is at the origin (0,0,0) of FCC structure), determine (1) How many Cu atoms (nearest neighbors) can directly jump to this vacancy
Answer:
6
Explanation:
FCC is face centered cubic lattice. In FCC structure, there are eight atoms at the eight corner of the cubic unit cell and one atom centered in each of the faces. FCC unit cells consist of four atoms, (8/8) at the corners and (6/2) in the faces.
Given that, Cu has FCC structure and it contains a vacancy at origin (0, 0, 0). And there is no other vacancy directly adjacent to the vacancy at the origin. So, all the adjacent positions contain Cu atoms. Hence, the total number of adjacent atoms of the vacancy at origin can jump into this vacancy.
the above FCC unit cell clearly indicates that there are six adjacent atoms adjacent to the vacancy at origin
So, the total number of adjacent atoms of the vacancy at origin can jump into this vacancy is 6.
What part of the food. chain is a pine?
a:primary consumer
b:secondary consumer
c:herbivore
d:producer
Answer:
producer
Explanation:
Based on the procedure, which of the following are reasonable sources of errors in determining heat lost or gained? One or more answers are correct and you will receive negative points for incorrect answers. Group of answer choices The cap of the calorimeter was not closed immediately after mixing. The final temperature was measured before the temperature stopped changing. Temperatures were not measured right before mixing. Volumes of solutions were not measured accurately.
Answer:
The possible source of errors as regard the Procedure are:
The final temperature was measured before the temperature stopped changing The cap of the calorimeter was not closed immediately after mixing temperatures where not measured right before mixingExplanation:
The procedure referred to should a experiment with regards heat
The possible source of errors as regards the Procedure are:
The final temperature was measured before the temperature stopped changing The cap of the calorimeter was not closed immediately after mixing temperatures where not measured right before mixingfind the percentage of mass in each of the element Ca ( HCO3)2 (Ca= 40, H = 1, O = 16, C= 35)
Answer:
% Ca = 24.69%
% H = 1.2%
% C = 14.8%
% O = 59.25%
Explanation:
The percentage by mass of each element can be calculated by dividing the mass of each element in the compound by the molar mass of the compound.
Molar mass of Ca(HCO3)2
Where; (Ca= 40, H = 1, O = 16, C= 12)
= 40 + {1 + 12 + 16(3)}2
= 40 + {13 + 48}2
= 40 + {61}2
= 40 + 122
= 162g/mol
- % mass of Ca = 40/162 × 100
= 0.2469 × 100
= 24.69%
- % mass of H = 2/162 × 100
= 0.012 × 100
= 1.2%
- % mass of C = 24/162 × 100
= 0.148 × 100
= 14.8%
- % mass of O = 96/162 × 100
= 0.5925 × 100
= 59.25%
What did Dalton compare atoms to?
A. Wood
B. Jacks
C. Marbles
D. Leaves
Explanation:
the answer is C marbles hope you find it helpful
For many purposes we can treat propane (CH) as an ideal gas at temperatures above its boiling point of - 42°C. Suppose the temperature of a sample of propane gas is lowered from 25.0°C to - 22.0 °C, and at the same time the pressure is changed. If the initial pressure was 0.58 kPa and the volume decreased by 40.0%, what is the final pressure?
Answer: The final pressure is 0.81 kPa
Explanation:
The combined gas equation is,
[tex]\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}[/tex]
where,
[tex]P_1[/tex] = initial pressure of gas = 0.58 kPa
[tex]P_2[/tex] = final pressure of gas = ?
[tex]V_1[/tex] = initial volume of gas = v
[tex]V_2[/tex] = final volume of gas = [tex]v-\frac{40}{100}\times v=0.6v[/tex]
[tex]T_1[/tex] = initial temperature of gas = [tex]25^0C=(25+273)K=298K[/tex]
[tex]T_2[/tex] = final temperature of gas = [tex]-22^0C=(-22+273)K=251K[/tex]
Now put all the given values in the above equation, we get:
[tex]\frac{0.58\times v}{298}=\frac{P_2\times 0.6v}{251}[/tex]
[tex]P_2=0.81kPa[/tex]
The final pressure is 0.81 kPa
Phosphoric acid is neutralized by potassium hydroxide according to the following reaction:
KOH (aq) + H3PO4 (aq) → K3PO4 (aq) + H2O (1)
What is the concentration of a phosphoric acid solution if 25.0 mL are exactly neutralized by 20.0 mL of 2.000 M KOH solution?
pleaseeeee helpppp!!!!!!
Answer:
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If 8 moles of magnesium chloride react with enough aluminum, how many moles
of aluminum chloride are produced?
If 8 moles of magnesium chloride react with enough aluminum then the amount of aluminum chloride produced is 5.3 mole.
What is aluminum?Aluminum is defined as a chemical substance with the atomic number 13 and the symbol Al. Aluminum has a density that is around one third that of steel, which is lower than that of most common metals. It has a strong affinity for oxygen, and when exposed to air, creates a protective oxide coating on the surface.
3 moles MgCl2and 2 moles Al will produce 3 moles Mg and 2 moles AlCl3.Therefore, if 8.0 moles of MgCl₂ react, the amount of ammonium chloride that may hypothetically be created can be calculated using the mole ratio between MgCl₂ and AlCl₃ .
8.0 mole MgCl₂ x 2 mole AlCl₃ / 3mol MgCl₂
= 5.3 mole AlCl3
Thus, if 8 moles of magnesium chloride react with enough aluminum then the amount of aluminum chloride produced is 5.3 mole.
To learn more about aluminum, refer to the link below:
https://brainly.com/question/9496279
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(giving brainiest) solve please!
Answer:
The water cycle shows the continuous movement of water within the Earth and atmosphere. It is a complex system that includes many different processes. Liquid water evaporates into water vapor, condenses to form clouds, and precipitates back to earth in the form of rain and snow. Water in different phases moves through the atmosphere (transportation). Liquid water flows across land (runoff), into the ground (infiltration and percolation), and through the ground (groundwater). Groundwater moves into plants (plant uptake) and evaporates from plants into the atmosphere (transpiration). Solid ice and snow can turn directly into gas (sublimation). The opposite can also take place when water vapor becomes solid (deposition).
How much mass of water (H₂O) do I need to mass out if I need 2.5 moles for a reaction?
Answer:
45g
Explanation:
Use the Mole = Mass x Mr equation:
Rearrange the above equation to find mass,
Mass = 2.5 moles x 18 (Mr of H₂O) = 45g
Therefore answer is 45g
Answer:
Given
number of moles (n) =2 . 5 mol
R.tc maas of H2O (m) =?
sln
H2O =(1x2+16)
=18g/mol
n=m/mr
m=nxmr
m=2.5x18
m=45g
mass of water is 45g
1.25 mol naoh (s) dissolves in water
what is meant by chemical combination? what are the laws of chemical combination?
Answer:
In simple terms, this law states that matter can neither be created nor destroyed. In other words, the total mass, that is, the sum of the mass of reacting mixture and the products formed remains constant.
Explanation:
please give me brain list and follow
What does water vapor do to the density of the air
Answer:
The amount of water vapor in air influence density. Water vapor is relatively light compared to diatomic Oxygen and diatomic Nitrogen - the dominant components in air. When vapor content increases in moist air the amount of Oxygen and Nitrogen are decreased per unit volume and the density of the mix decreases since the mass is decreasing.
Explanation:
When aqueous ammonia is added to a solution containing Bi3+ and Cu2+ cations, ____________ occurs. A. Reduction to black bismuth metal.B. Precipitation of a black bismuth hydroxide.C. Precipitation of white bismuth hydroxide. D. Formation of a red-brown precipitate of Cu2[Fe(CN)6].
Answer:
C. Precipitation of white bismuth hydroxide.
Explanation:
When aqueous ammonia is added to a solution that has Bi3+ and CU2+ cations, what we would have as a chemical result is the precipitation of white Bismuth hydroxide.
The chemical reaction for this can be written as,
Bi3+ + 2NH3 + 3H2O ⇌ Bi(OH)3(s) + 3NH4
Thank you!
Which of the following safety devices ensures that electricity will flow through it when flowing "downhill" instead of through people? A. Surge protectors B. Electric generators C. Ground wires D. Special plugs for high-current devices
Answer:
Ground Wires
Explanation:
does water burn? for my sister that says water does burn
Answer:
No, water doesn't burn. It only can burn under specific conditions in a lab.
Explanation:
PLZZZ HELP. Just say yellow goes under ..... for example.
Answer:
yellow goes under...... for example.
What is the mass of 2.9 moles of calcium? Explain please
Answer:
116 g
Explanation:
From the question given above, the following data were obtained:
Number of mole of calcium = 2.9 moles
Mass of calcium =.?
The mole and mass of a substance are related according to the following formula:
Mole = mass / molar mass
With the above formula, we can obtain the mass of calcium. This can be obtained as follow:
Number of mole of calcium = 2.9 moles
Molar mass of calcium = 40 g/mol
Mass of calcium =.?
Mole = mass / molar mass
2.9 = mass of calcium / 40
Cross multiply
Mass of calcium = 2.9 × 40
Mass of calcium = 116 g
Therefore, the mass of 2.9 moles of calcium is 116 g.
Did a chemical reaction occur while the candle was burning?
Answer: yes
Explanation:
Which of these rules are applicable for naming covalent compounds?
In an alternate universe the reaction between acid and base is endothermic. 20.0 mL of 0.200 M monoprotic acid dissolved in water and 50.0 mL of 0.100 M monoprotic base dissolved in water were mixed in a coffee-cup calorimeter. The density of the solution is 2.010 g/mL. The specific heat of the solution is 4.00 J/gK. The temperature changed by -13.57 degrees Celsius (i.e., decreased by that much). Calculate the enthalpy of reaction on kJ/mol limiting reagent
Explanation:
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