Answer:
Lead sulfide.
Explanation:
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
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.
5) A scientist adds 1.2 liters of water to a 5.0 liter solution, causing the molarity to become 0.4 M. What was the molarity of the initial solution before the dilution?
Explanation:
i hope i helped you in this problem
According to the molar concentration, the molarity of the initial solution before the dilution is 0.096 M.
What is molar concentration?Molar concentration is defined as a measure by which concentration of chemical substances present in a solution are determined. It is defined in particular reference to solute concentration in a solution . Most commonly used unit for molar concentration is moles/liter.
The molar concentration depends on change in volume of the solution which is mainly due to thermal expansion. Molar concentration is calculated by the formula, molar concentration=mass/ molar mass ×1/volume of solution in liters.
In terms of moles, it's formula is given as molar concentration= number of moles /volume of solution in liters.Substitution of values in formula M₁V₁=M₂V₂ gives M₁= 0.4×1.2/5=0.096 M.
Thus, the molarity of the initial solution before the dilution is 0.096 M.
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Predict the shape of the molecule.....
Answer:
bent
Explanation:
find 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%
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:
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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우린 탁 쏴 마치 콜라지
너의 각막 깜짝 놀라지
꽤 꽤 폼나지 포 포 폼나지
Select the correct algebraic form for the equation to be used for this calculation.
n equals StartFraction R T over P V EndFraction.
n equals StartFraction P V over R T EndFraction.
n equals StartFraction R V over P T EndFraction.
Answer:
55.9 kPa
Explanation:
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:
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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Did a chemical reaction occur while the candle was burning?
Answer: yes
Explanation:
What part of the food. chain is a pine?
a:primary consumer
b:secondary consumer
c:herbivore
d:producer
Answer:
producer
Explanation:
(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).
Helpppp me pleaseeee now I’ve been struggling so bad w this
Answer:
I don't know what the passage says, but I feel like the most logical conclusion is D or the last one.
Explanation:
Answer:
D! Hope this helps! Figured id help with all of ur questions!
Explanation:
Im a wiz at science! ;)
1.25 mol naoh (s) dissolves in water
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
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 mixing
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:
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
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:
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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.
Part A
Choose the paramagnetic species from below.
O He
O Te
O T14+
O All of the above are paramagnetic.
None of the above is paramagnetic.
Answer:
o He
Explanation:
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PLZZZ HELP. Just say yellow goes under ..... for example.
Answer:
yellow goes under...... for example.
In the following reaction:
C6H6 + Br2 → C6H5Br + HBr
Assume 1.25 moles of C6H6 react with sufficient bromine, how many moles of C6H5Br should form?
2.50 mol
5.00 mol
0.625 mol
1.25 mol
Answer:
1.25mol
Explanation:
The equation you gave is balanced and everything is in a 1:1:1:1 ratio. Because there is excess bromine, the reaction can proceed until completion which will give you 1.25 mol C6H5Br
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:
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
Wch of the following phrases is the best definition of science?
A. Research that determines the behavior of the physical world
B. Observation of the physical world
C. Knowledge that governs the physical world
D. A set of predictions that interpret patterns in the physical world
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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.
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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!