Answer:
2
Nobody is able to foresee the solubility of a product. There are some experimental rules, but they all have exceptions, that nobody is able to explain.
Just have a look on the Calcium salts made with the halogens (F, Cl, Br, I). There is a nice analogy among Cl, Br and I, but not F. Look ! The Calcium chloride CaCl2, bromide CaBr2 and iodide CaI2 are all extremely soluble in water. They are all soluble in less than their weight of water. But calcium fluoride CaF2 is among the least soluble product on Earth. The principal mineral for Fluoride is CaF2, and it can be found everywhere at the surface of the Earth. If this mineral would have been at least a little soluble in water, the rains would have washed away this mineral in the geological times. Why is there such a huge difference between calcium fluoride and the other halogenides ? Nobody knows !
Another example. Potassium perchlorate is the only potassium salt which is very weakly soluble in water. By comparison, Sodium perchlorate is extremely soluble in water. Why? Another example: the number of Silver compounds which are soluble in water is limited. In organic solvents, it is even worse. But the Handbook of Chemistry and Physics says that Silver perchlorate is soluble in toluene. Why? Nobody knows.
From time to time there are articles published in journals like the Journal of Chemical Education. The author is proud of displaying a theory filled with new parameters, for explaining the solubility of quite a lot of chemicals. But there are always exceptions, that he regrets not to be able to explain.
Which of the following is a scientific question?
O A. Who made the first plant-hardiness zone map?
O B. Which plants are sold by my local nursery?
O c. Which kind of flowers should I plant in my garden?
O D. How does gravity affect the growth of plant roots?
I need help can someone please explain to me why this B is the correct answer I have a photo of the question
I know B is the correct answer I just need help knowing why it’s B
Answer:
9 g
Explanation:
Chemical equation:
CH₄ + 2O₂ → CO₂ + 2H₂O
4 16 11 9
4+16 = 20 11+9 = 20
9 gram of water must be produced because according to law of conservation of mass, mass neither created nor destroyed thus on both side of equation mass must be same.
Law of conservation of mass:
According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.
This law was given by French chemist Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.
For example:
6CO₂ + 6H₂O + energy → C₆H₁₂O₆ + 6O₂
there are six carbon atoms, eighteen oxygen atoms and twelve hydrogen atoms on the both side of equation so this reaction followed the law of conservation of mass.
If a substance has a PH of 7 is it a acid, base or a neutral.
Answer:
Neutral
Explanation:
A pH below 7 is acidic and a pH above 7 is basic, and a pH of 7 is neutral.
What do ionic bonds contain?
Answer:
Valence Electrons
Explanation:
Answer:
Ionic bonds contain electrovalent bond
Explanation:
Ionic bond, also called electrovalent bond, type of linkage formed from the electrostatic attraction between oppositely charged ions in a chemical compound. Such a bond forms when the valence (outermost) electrons of one atom are transferred permanently to another atom.
The growth of a plant toward light is called _____.
phototropism
tropism
geotropism
It's called phototropism
Answer:
The answer is (Phototropism)
Can the process of rusting be called combustion?
Answer:
no the answer is oxidation
What are the single sugars that are the building blocks of carbohydrates?
Answer:
Monosaccharides, these are the simplest building block of carbs
Explanation:
Which of the following most likely happens when thermal energy is removed from a chemical reaction?
Answer:
fewer collisions occur between particles or lowering the temperature
Explanation:
HELP PLEASE!!!!!!!!
what coefficient will go in the box
Answer:
5
Explanation:
I don't remember very thing from this unit but I believe 5 makes it possible
Which equation represents a double replacement reaction?
A) 2 Na + 2 H2O → 2 NaOH + H2
B) CaCO3 → CaO + CO2
C) LiOH + HCl → LiCl + H2O
D) CH4 + 2 O2 → CO2 + 2 H2O
Answer:
C) LiOH + HCl → LiCl + H₂O
General Formulas and Concepts:
Chemistry - Reactions
Synthesis Reactions: A + B → AB Decomposition Reactions: AB → A + B Single-Replacement Reactions: A + BC → AB + C Double-Replacement Reactions: AB + CD → AD + BCExplanation:
Step 1: Define
RxN A: 2Na + 2H₂O → 2NaOH + H₂
RxN B: CaCO₃ → CaO + CO₂
RxN C: LiOH + HCl → LiCl + H₂O
RxN D: CH₄ + 2O₂ → CO₂ + 2H₂O
Step 2: Identify
RxN A: Single Replacement Reaction
RxN B: Decomposition Reaction
RxN C: Double Replacement Reaction
RxN D: Combustion Reaction
The speed of a mechanical wave through a medium depends on the type of medium. It also depends on the type of mechanical wave. Which statement is true?
The statements are;
A) All waves travel at the same speed if no medium is present.
B) Electromagnetic waves require a medium, but mechanical waves do not.
C) All waves travel at the same speed through any medium.
D) Mechanical waves require a medium, but electromagnetic waves do not.
Answer:
Statement D is true.
Mechanical waves require a medium, but electromagnetic waves do not.
Explanation:
The two types of waves are;
Mechanical waves and Electromagnetic waves.
Mechanical waves require a medium, such as an atmosphere or water, to enable it transport its energy. For example sound waves occur when you clap and thereby distort the air around.
Whereas, Electromagnetic waves do not require a medium to enable it transport its energy. A good example would be light. Normally, Electromagnetic waves are usually formed when the electric field and the magnetic field are perpendicular to each other.
So electromagnetic waves can transmit without a medium because electric and magnetic fields can exist independently without a medium.
What is the half life of quartz??
Answer:
1.36 Myr or 717 kyr.
Explanation:
Answer:
Half life of quartzs means natural decay of radioactive material.
Explanation:
Rust forms when iron metal reacts with oxygen gas. Which chemical reaction best
supports the law of conservation of mass?
A. Fe + O2 --> Fe2O3
B. 2Fe + O2 --> 2Fe2O3
C. 3Fe + 202 --> Fe2O3
D. 4Fe + 302 --> 2Fe2O3
Answer:
D. 4Fe + 302 --> 2Fe2O3
Explanation:
The equation that bests supports the law of conservation of mass is the choice D;
4Fe + 3O₂ → 2Fe₂O₃
Based on the law of conservation of mass, the number of atoms on both sides of the expression must be the same. Only the fourth choice proves this law;
4Fe + 3O₂ → 2Fe₂O₃
Number of atoms
Elements Left hand side Right hand side
Fe 4 4
O 6 6
We can see that both side of the expression have the same number of atoms and the equation is balanced.
What are the first two levels of cellular organization?
Answer:
Cells and tissue
Explanation:
Cells are the smallest functional units of all living things
Tissue is organic material from which organs and their bodily structures appear
collectiveness leads to a good society? how
Answer:
A good society has a transparent talk, they share all matters related to the society, hence everyone knows what's going on. This is why collectiveness leads to a good society.
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A beaker filled with 100 ml of water has an initial temperature of 23 degrees Celsius. After the beaker has been heated, the final temperature is 100 degrees celsius. The final volume of the water is 85.32 ml. After reaching the final temperature, there are bubbles throughout the water. What is this an example of?
Answer: The temperature of a beaker of water is 318.2 K.
Explanation:
Multiplying the temperature in Celsius by tells us how many Fahrenheit degrees above the freezing .
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Answer:
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Answer:
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Explanation:
common sense
Here is the electron configuration for Magnesium. How many total electrons are in the 2nd energy level?
Mg: 1s2 2s2 2p6 3s2
Answer:
8 electrons
Explanation:
Magnesium is present on group 2.
It has 2 valence electrons.
Electronic configuration of magnesium:
Mg₁₂ = 1s² 2s² 2p⁶ 3s²
1st energy level contain 2 electrons.(1s²)
2nd energy level contain 8 electrons. (2s² 2p⁶)
3rd energy level contain 2 electrons. (3s²)
3rs energy level of magnesium is called valence shell. It contain two valance electrons. Magnesium can easily donate its two valance electrons and get stable electronic configuration.
It react with halogens and form salt. For example,
Mg + Cl₂ → MgCl₂
Question 2 (1 point)
Which of the following is the main reason the transition metals are able to exist in different forms?
а.
predictability in ability to bond
B.
unfilled d orbitals
C.
magnetic properties
D.
predictability in number of valence electrons
Answer:
B. Unfilled d orbitals
Explanation:
How many phases of matter are there? two, three, four or five?
Answer:
There are four phases of matter.
Explanation:
There are the three phases you normally hear about: solid, liquid and gas.
However, there is also a fourth named plasma.
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At 25ºC, gas in a rigid cylinder with a movable piston has a volume of 145 mL and a pressure of 125 kPa. Then the gas is compressed to a volume of 80. ML. What is the new pressure of the gas if the temperature is held at 25ºC?
Answer:
P2 = 226.6 kPa (Approx)
Explanation:
Given:
Temperature t = 25ºC
Old volume v1 = 145 ml
Old pressure p1 = 125 KPa
New volume v2 = 80 ml
Find:
New pressure p2
Computation:
p1v1 = p2v2
125 x 145 = P2 x 80
P2 = 226.6 kPa (Approx)
A student weighed an empty graduated cylinder. It weighed 35.86 g. She then carefully added water to the graduated cylinder until it reached the 7.5 mL mark. When she weighed the graduated cylinder again, this time with the 7.5 mL of water in it, it weighed 43.18 g. What was this student's experimental density of water? A relationship between the number of pennies and density
Question:
A student weighed an empty graduated cylinder. It weighed 35.86 g. She then carefully added water to the graduated cylinder until it reached the 7.5 mL mark. When she weighed the graduated cylinder again, this time with the 7.5 mL of water in it, it weighed 43.18 g. What was this student's experimental density of water?
Answer:
0.976 g/mL
Explanation:
Weight of empty cylinder = 35.86g
Volume of water = 7.5mL
Weight of cylinder + water = 43.18g
Experimental density = ?
Density of water = Mass of water / volume of water
Mass of water = (Weight of cylinder + water) - Weight of empty cylinder
Mass of water = 43.18 - 35.86 = 7.32g
Density = 7.32 / 7.5 = 0.976 g/mL
how many sig figs are in 1.008 and 120.9??
Answer:
there are 4 sig figs in 120.9 and there are 4 sig figs in 1.008
Explanation:
P and Q are two substances such that the melting point of P and the boiling point of Q are the same. If P is a solid at a certain temperature, what state will Q be in at the same temperature?
Answer:
Explanation:
Firstly, it should be noted that melting and freezing points are the same. Thus, when a substance melts at a certain temperature, it means it can also start freezing/solidifying at that same temperature. That been said, when the substance P is a solid at a certain temperature, the other compound Q will boil at that same temperature and hence will be a gas at that same temperature.
If P is solid, it simply means that Q must still be in the liquid state.
From the question, we can see that, the melting point of P and the boiling point of Q are the same. The melting point of a substance is the temperature at which the solid turns to liquid while the boiling point of a substance is the temperature at which a liquid turns to a gas.
If P is solid, it simply means that Q must still be in the liquid state. It has not yet started boiling since the melting point of P and the boiling point of Q are the same.
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CO2(g) +H2(g)------>CO(g) + H2O(/)
What is being oxidized?
Carbon
Carbon Dioxide
Oxygen
Hydrogen
Answer:
Srry its so hard
Explanation:
describe how metamorphic rocks are formed by heat and pressure
Answer:
Metamorphic rocks form when heat and pressure transform an existing rock into a new rock. Contact metamorphism occurs when hot magma transforms rock that it contacts. Regional metamorphism transforms large areas of existing rocks under the tremendous heat and pressure created by tectonic forces.
Explanation:
1. How many times will a mole of paperclips (think giant paperclip chain) stretch around the equator of the
earth? (1 paperclip = 0.030 m, Earth's circumference = 4.00 x 10m)