Answer:
C-The principal because he or she controls all the activity in the school
9. Carbon-14 has a half-life of 5,730 years. How many years have passed after 3
half-lives?
Answer:
120 gram sample of a radioactive element, how many grams of that element will be left after 3 half-lives have passed? If you have a 300
Explanation:
Hope this helps!
3. Ni(NO2)3
What’s the name for the formula
PLEASE CAN SOMEONE PLEASE HELP ME I CAN'T DO IT :(
CaCO3 + H2SO4 __________ + H2O + CO2
Na2CO3 + __________ 2NaCl + H2O + CO2
Answer:
H2SO4 + CaCO3 → CaSO4 + H2O + CO2 - Balanced equation | Chemical Equations online!
Na2co3 HCL nacl h2o co2
This is an acid-base reaction (neutralization): Na 2CO 3 is a base, HCl is an acid. This is a gas evolution reaction, CO 2 is the formed gas.
How do you solve -8r=240
Answer:
You solve that dividing beach term by -8 and simplifying which for this answers will give you r=-30
Explanation:
Pls correct me if I’m wrong.
Hope this helps :)
What is the total number of joules required to freeze a 10 g sample of water at 0°C?
show work if possible and will give brainliest
Explanation:
the answer will be 98.4 kJ
As per concept of enthalpy of fusion , 98,397 joules of energy are required to freeze 10 g of water at 0°C.
What is enthalpy of fusion?Enthalpy of fusion is defined as the enthalpy change which results from when a substance changes its state from solid to a liquid at a constant pressure.Heat of solidification is opposite of enthalpy of fusion.During fusion there is a phase transition which takes place, from liquid to solid.
The temperature at which the fusion takes place is called as the fusion temperature. This enthalpy is accompanied without any change in temperature.
Enthalpy of fusion of water=333.55 J/g . This value is for 1 g of water as per definition,hence for 10 g water enthalpy of fusion is 10×333.55=3335.5 J.
Hence, 3335.5 joules are required for freezing 10 g sample.
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Rafa places some copper into a solution of sodium chloride. No reaction takes place. Using the displacement theory, explain why no reaction took place?
Na more reactive than Cu
Further explanationGiven
Copper in a solution of NaCl
Required
The displacement theory
Solution
A single replacement reaction is a chemical reaction in which one element replaces the other elements of a compound to produce new elements and compounds
Not all of these reactions can occur. We can use the activity series, which is a list of elements that can replace other elements below / to the right of them in a single replacement reaction.
The voltaic series:
Li-K-Ba-Ca-Na-Mg-Al-Mn- (H2O) -Zn-Cr-Fe²⁺-Cd-Co-Ni-Sn-Pb- (H) -Cu-Hg-Fe³⁺-Ag-Pt-Au
The electrode which is easier to reduce than the hydrogen (H2) electrode has a positive sign (E red= +) and is located to the right of the voltaic series (right of H)
The electrode which is easier to oxidize than the hydrogen (H2) electrode and is difficult to experience reduction has a negative sign (E red= -) and is located to the left of the voltaic series (left of H)
Reaction
Cu + NaCl≠
The existing copper element can not replace the sodium element, which is on the left side so the reaction will not occur.
But if it is reversed, then a reaction can occur
2 Na + CuCl2 → Cu + 2 NaCl
what must happen for heat to be transferred by thermal conduction?
The transfer of heat between substances by thermal conduction is only possible when they are in direct contact with each other.
What is Thermal Conduction ?The transfer of heat from the hotter end to the colder end of object is known as conduction.
The spontaneous flow of Heat from a hotter to a colder body ie, heat is conducted from the hotplate of an electric stove to the saucepan when it is in contact with it.
The better the conductor, the more rapidly heat will be transferred.
Thus, The transfer of heat between substances by thermal conduction is only possible when they are in direct contact with each other.
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is CdCi2 covalent or ionic
Answer:
binary and 11
Explanation:
CaCl2 or Calcium Chloride is an ionic bond and not a covalent bond. Since there should be sharing of electrons between two atoms to be a covalent bonding. In case of calcium chloride, the calcium gives up an electron to each chlorine atom, becoming Ca2+ ions and chlorine become Cl– ions.
:)
Copper (ii) carbonate decomposes to form copper (ii) oxide grains and carbon dioxide gas is given off.
Answer:
yes
Explanation:
The correct equation for the decomposition of copper carbonate is:
CuCO3 → CuO + CO2
Energy exists in different forms. Which of the following forms of energy best describes the energy stored
in food?
A. electromagnetic energy
B. mechanical energy
C. sound energy
D. chemical energy
Answer:
D. chemical energy
Explanation:
Food contains chemical energy as chemical energy is stored in bonds.
9. I have the lowest electronegativity of the nonreactive elements. My family name is ____________. I am classified as a ___________. I have _____________ valence electrons.
Answer:
I have the lowest electronegativity of the nonreactive elements. My family name is alkali metals. I am classified as a reactive metal. I have one valence electrons.
Explanation:
Electronegativity refers to the ability of the atoms of an element to attract electrons to itself. Based on their nature, non-metals are electronegative elements whereas metal are electropositive as they have a tendency to give up their electrons rather than attract electrons to themselves.
In the periodic table of elements, non-metallic character, and hence, electronegativity increases from left to right across a period, and decreases down a group. The most electropositive element is fluorine. On the other hand, electropositivity decreases across a period from left to right but increases on going down a group. Hence, the most electropositive element is Francium. This also means that Francium is the least electronegative element,
francium belong to the group 1A of the periodic table which are the most reactive metals. The family of group 1A elements are known as alkali metals. They possess only one valence electron which they easily give up to form univalent positive ions or cations. Francium is a radioactive element.
In a submarine beneath the ocean’s surface, a captain peered into a long tube to see possible threats in the sea and air above. This sight tube, called a periscope, was designed by the Frenchman Marie Davey in 1854. Davey’s periscope contained two mirrors, one placed at each end of a vertical tube. The mirrors were set parallel to each other and at 45 degrees to the vertical. The reflective surfaces faced each other. When light from an object on the surface reflected downward, an image appeared to the eye. People in submerged submarines could see what was above them!
Imagine you are in a submerged submarine looking through a periscope. What are some things you might see?
How does the number of protons compare to the number of
electrons in a canton
Answer: The number of protons in cation is more than the number of electrons
Explanation:
cations are positive ions that means that they lose electrons to be stable nd have electron configuration (atomic number ) equivalent to the preceding noble gas
as : sodium 11 , it loses on electron to be stable and its electron configuration is equivalent to neon 10
so ,the number of protons in cation is more than the number of electrons
i hope it helps!
How many liters are in 100g of CoCl2?
Answer:
0.77018342688495
Explanation:
I did this
What is the molarity of a solution that has 2.87 moles of NaCl in 5020 mL of solution?
1. What do microorganisms share in common?
Answer:
Bacterial species are typified by their diversity. There are three notable common traits of bacteria, 1) lack of membrane-bound organelles, 2) unicellular and 3) small (usually microscopic) size.
Explanation:
What Are the Characteristics Common to All Bacteria?
Single-Celled. Perhaps the most straightforward characteristic of bacteria is their existence as single-celled organisms. ...
Absent Organelles. ...
Plasma Membrane. ...
Cell Walls. ...
DNA.
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1000 L of nitrogen and 2400 L of hydrogen are mixed to produce ammonia. The volume of ammonia produced is
A. 1200 L
B. 1000 L
C. 2400 L
D. 1600 L
Answer: D. 1600 L
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.
To calculate the moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given volume}}{\text {Molar volume}}[/tex]
[tex]\text{Number of moles of nitrogen}==\frac{1000L}{22.4L}=44.6moles[/tex]
[tex]\text{Number of moles of hydrogen}==\frac{2400L}{22.4L}=107.1moles[/tex]
[tex]N_2(g)+3H_2(g)\rightarrow 2NH_3(g)[/tex]
According to stoichiometry :
3 moles of [tex]H_2[/tex] require 1 mole of [tex]N_2[/tex]
Thus 107.1 moles of [tex]H_2[/tex] will require=[tex]\frac{1}{3}\times 107.1=35.7moles[/tex] of [tex]N_2[/tex]
Thus [tex]H_2[/tex] is the limiting reagent as it limits the formation of product and [tex]N_2[/tex] is the excess reagent.
As 3 moles of [tex]H_2[/tex] give = 2 moles of [tex]NH_3[/tex]
Thus 107.1 moles of [tex]H_2[/tex] give =[tex]\frac{2}{3}\times 107.1=71.4moles[/tex] of [tex]NH_3[/tex]
Volume of [tex]NH_3=moles\times {\text {Molar volume}}=71.4moles\times 22.4L/mol=1600L[/tex]
Thus volume of ammonia produced is 1600 L
MAX TEN MINUTES PLZZZZZ HURRY
Essential Question:
How does the transfer of thermal energy become minimized or maximized?
explain you hypothisith
Answer:
when it reduces heat.
Explanation:
Thermal energy is transferred to material,the motion of its particles speeds up and it's temperature differences.Insulating materials are bad conductors and so this reduces the heat loss by conduction.The material also prevents air circulating inside the cavity,therefore reducing heat loss by convection.Heat loss through the roof can be reduced by laying loft insulation.
If the price of peaches increases, what can be expected?
More peaches will be sold.
Fewer peaches will be sold.
The number of peaches sold will be unaffected.
Peach orchards will produce less fruit.
Answer:
fewer peaches will be sold
Explanation:
if the price increases less people will want to buy it, but the orchards would still get money so they wouldnt be affected
Answer:
fewer peaches
Explanation:
Carbon exists in many forms on Earth. The diagram below shows part of the carbon cycle. What is happening in Step 1? *
1 point
Captionless Image
Animals are decomposing and releasing carbon into the soil.
Animals are breaking down organic molecules and releasing carbon dioxide into the atmosphere.
Animals are releasing energy into the environment and storing carbon.
Animals are converting carbon dioxide from the atmosphere to oxygen.
The first step of carbon cycle is animals are breaking down organic molecules and releasing carbon dioxide into the atmosphere.
What is a carbon cycle?Carbon cycle completes into four steps: photosynthesis, decomposition, respiration, and combustion.
In the first step, carbon enter the environment by respiration, and in the second step, carbon dioxide is consumed by plants.
Thus, the correct option is B.
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why is there no reaction between copper and sodium chloride
remember I am talking of copper alone and not copper sulfate.
Answer:
If the solution is not in contact with air, nothing will happen. If the solution is in contact with air, it will be not a reaction between copper, water and sodium chloride..
in the end there will be no reaction
What is the most likely effect of an increase in precipitation?
Lakes dry up. Shortage of water. Decrease in humidity.
Q.3 Which the following statements about the given reaction are correct:
3Fe(s) + 4H2O(g)- Fe203 (S) + 4H2(g)
i) Iron metal is getting oxidized
ii) Water is getting reduced
iii) Water is acting as reducing agent
iv) Water is acting as oxidizine agent
a) (i), (ii) and (iii) b)(iii) and (iv)
c) (i), (ii) and (iv) d) (ii) and (iv)
Answer:
The statements which are correct are;
c) (i), (ii) and (iv)
Explanation:
The chemical equation is presented as follows;
2Fe(s) + 3H₂O(g) → 3Fe₂O₃(s) + 3H₂(g)
Therefore, we have;
i) The iron gains oxygen atoms and therefore gets oxidized
The iron loses 3 electrons each to become oxidized to Fe³⁺ in Fe₂O₃
ii) The water loses oxygen and therefore it is getting reduced
iv) The water donates oxygen and therefore it is acting as the oxidizing agent
The correct options are (i), (ii) and (iv).
Leila made herself a cup of hot chololate weighing 150 grams. If she started with 125 grams of milk, how many grams of hot chocolate mix did she add?
Answer:
150g-125g
=25 of hot chocolate mix
Why is water said to be universal solvent?
A.it dissolves some substances.
B.It dissolves almost all substances
C.It is dissolved by some substances.
D.It is dissolved by almost all substances.
Answer:
B
Explanation:
And, water is called the "universal solvent" because it dissolves more substances than any other liquid. This allows the water molecule to become attracted to many other different types of molecules.
Answer:
I believe it's B
Explanation:
Water can dissolve with any that's why it's universal and can dissolve substancrs more than any other Liquid.
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If 5.3 moles of magnesium phosphate react with excess sodium chloride how many moles of magnesium chloride will be formed?
what are oil and waters properties of matter?
Answer:
Two other beneficial properties of the oil include the inhibition of corrosion of metal surfaces, such as steel, and the removal of dirt and detritus via detergency.
Properties of water include its chemical formula H2O, density, melting, boiling point & how one molecule of water has two hydrogen atoms covalently bonded to one oxygen atom.
Turgor pressure can help plants move. Internal water pressure can cause -
true or false
sugar melting an example of oxidation
and
water evaporating
Answer:
false i think
Explanation:
what is a compound?
Answer:
NOUN
a thing that is composed of two or more separate elements; a mixture
Explanation:
basically a mixture