Answer:Exothermic reactions are reactions or processes that release energy, usually in the form of heat or light. In an exothermic reaction, energy is released because the total energy of the products is less than the total energy of the reactants.
Explanation:lol
which evidence is an indication that a chemical reaction has occured
Answer:
color change
Explanation:
PLEASE HELP FAST!!
If metal X is lower than metal Y on the activity series, then:
A. X will react in water, but only if the temperature is low enough
B. Y will form oxides of X, but only indirectly
C. X will replace ions of Y in a solution
D. Y will replace ions of X in a solution
Answer:
D. Y will replace ions of X in a solution
Explanation:
If metal X is lower than metal Y on the activity series, then Y will replace ions of X in a solution.
This is the crux of single displacement reactions.
In a single displacement reaction, a metallic ion in solution is replaced by a metal higher in the activity series than the metal in solution. On the activity series, metals higher are more reactive and will displace the lower and less reactive ones. Reactivity increases up the group.determine the specific heat ofmaterial if a 12g sample absorbed 48j as it was heated from 20-40
Answer:
c =0.2 J/g.°C
Explanation:
Given data:
Specific heat of material = ?
Mass of sample = 12 g
Heat absorbed = 48 J
Initial temperature = 20°C
Final temperature = 40°C
Solution:
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree.
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = 40°C -20°C
ΔT = 20°C
48 J = 12 g×c×20°C
48 J =240 g.°C×c
c = 48 J/240 g.°C
c =0.2 J/g.°C
The most useful property of metalloids is their
(A) Varying ability to conduct electric current.
(B) Softness and malleability.
(C) Tendency to be unreactive.
(D) Ability to be pulled out into long wires.
Answer:
An element is the simplest form of matter that cannot be split into simpler substances or built from simpler substances by any ordinary chemical or physical method. There are 110 elements known to us, out of which 92 are naturally occurring, while the rest have been prepared artificially. Elements are further classified into metals, non-metals, and metalloids.
Table 2.11.1: Characteristic properties of metallic and non-metallic elements:
Distinguishing luster (shine)
Non-lustrous, various colors
Nonmetals
Elements that tend to gain electrons to form anions during chemical reactions are called non-metals. These are electronegative elements. They are non-lustrous, brittle and poor conductors of heat and electricity (except graphite). Non-metals can be gaseous, liquids or solids.
Physical Properties of nonmetals:
Physical State: Most of the non-metals exist in two of the three states of matter at room temperature: gases (oxygen) and solids (carbon).
Non-Malleable and Ductile: Non-metals are very brittle, and cannot be rolled into wires or pounded into sheets.
Conduction: They are poor conductors of heat and electricity.
Luster: These have no metallic luster and do not reflect light
Conductivity: Poor conductors of heat and electricity
Melting and Boiling Points: The melting points of non-metals are generally lower than metals
Seven non-metals exist under standard conditions as diatomic molecules:
H2(g)
N2(g)
O2(g)
F2(g)
Cl2(g)
Br2(l)
I2(l) (volatile liquid - evaporates readily)
Chemical Properties of Nonmetals
Non-metals have a tendency to gain or share electrons with other atoms. They are electronegative in character.
Nonmetals, when reacting with metals, tend to gain electrons (typically attaining noble gas electron configuration) and become anions:
Nonmetal + Metal -> Salt
3Br2(l)+2Al(s)→2AlBr3(s)(2.11.4)
Compounds composed entirely of nonmetals are molecular substances (not ionic).
They generally form acidic or neutral oxides with oxygen that that dissolve in water react to form acids:
Physical Properties of Metalloids
State: They are all solid at room temperature.
Conduction: Some metalloids, such as silicon and germanium, can act as electrical conductors under the right conditions, thus they are called semi-conductors.
Luster: Silicon for example appears lustrous, but is not malleable or ductile (it is brittle - a characteristic of some nonmetals). It is a much poorer conductor of heat and electricity than the metals.
Solid Solutions: They can form alloys with other metals.
Chemical Properties of Metalloids
Their physical properties tend to be metallic, but their chemical properties tend to be non-metallic.
The oxidation number of an element in this group can range from +3 to -2, depending on the group in which it is located.
Trends in Metallic and Nonmetallic Character
Metallic character is strongest for the elements in the leftmost part of the periodic table, and tends to decrease as we move to the right in any period (nonmetallic character increases with increasing ionization values). Within any group of elements (columns), the metallic character increases from top to bottom (the ionization values generally decrease as we move down a group). This general trend is not necessarily observed with the transition metals.
2.10: Electron Affinities 2.12: Electronegativity
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The LibreTexts libraries are Powered by otherwise noted, LibreTexts content is licensed by CC BY-NC-SA 3.0. Have questions or comments? For mor
Explanation:
its D
Answer:
(A) Varying ability to conduct electric current.
Explanation:
The most useful property of metalloids is their varying ability to conduct electric current.
Metalloids are elements or substances that shares properties that transcends between those of a true metal and non-metal.
Based on their properties that straddles those of metals and non-metals, they find good use in electronic parts. Most importantly because they have varying ability to conduct electric current. They conduct current under certain conditions.Organic materials are from ___________things.
A. Living
B. Dead
EASY POINTS
B trust me please ..........
Answer:
both
Explanation:
depends on what type because there is fecal material dead tissue decomposing soooo both
what will happen to the salt when mixed to liquid?
Answer:
the salt dissolves in water because of covalent bonds.
Explanation:
mark me brainliest.
What is true of the orbitals in the 3d energy level?
A. They have higher energy than 2s orbitals.
B. They have lower energy than 4f orbitals.
C. Together, the five 3d orbitals can hold 10 electrons.
D. All of the above are true.
Answer:
D. All of the above are true.
Explanation:
All the given options in the problem are true.
According to Aufbau's principle, the sublevels with lower energy are filled before those with higher energies.
The order of filling according to their energies is;
1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p
We see that the 3d energy level is lower than 4f but higher than 2s.
Also, the 3d orbital has 5 subshells and each can hold a maximum of two electrons.
This gives a capacity of 10 electrons.
Acetylene gas is often used in welding torches because of the very high heat produced when it reacts with oxygen gas, producing carbon dioxide gas and water vapor. Calculate the moles of oxygen needed to produce 0.095 of carbon dioxide. Be sure your answer has a unit symbol, if necessary, and round it to the correct number of significant digits.
Answer:
0.12 mol O₂
Explanation:
Step 1: Write the balanced combustion reaction
C₂H₂ + 2.5 O₂ ⇒ 2 CO₂ + H₂O
Step 2: Establish the appropriate molar ratio
We want to know the moles of oxygen needed to produce 0.095 moles of carbon dioxide. The molar ratio of O₂ to CO₂ is 2.5:2.
Step 3: Calculate the moles of oxygen needed to produce 0.095 moles of carbon dioxide
0.095 mol CO₂ × 2.5 mol O₂/2 mol CO₂ = 0.12 mol O₂
The initial concentration of reactants in a first order reaction is 0.27 M. The rate constant for the reactio is 0.75 s^-1. What is the concentration of reactants after 1.5sec?
Answer:
Final concentration = 0.019 M
Explanation:
Initial Concentration [A]o = 0.27M
Rate constant, k = 0.75 s^-1
Final concentration [A] = ?
Time, t = 1.5s
The relationship between the variables is given by the equation;
ln[A] = ln[A]o - kt
ln[A] = ln(0.27) - (0.75)(1.5)
ln[A] = - 1.309 - 1.125
ln[A] = - 2.434
[A] = 0.019 M
apples are considered carbons?
Answer:
- regular nitrogen balance, maintain healthy body weight and protein count does not change
- negative nitrogen balance, nitrogen intake is greater than nitrogen output, makes body weight and protein decrease caused by illness
-positive nitrogen balance, nitrogen intake is less than nitrogen output, increase muscle mass, protein increases, due to pregnancy or weight lifting
Explanation:
What does the electronegativity of an atom indicate?
A.
The tendency of the atom to pull on electrons
B.
The measurement of the charge of an ion
C.
The effect the valence electrons have on core electrons
D.
The energy required to gain or lose an electron
Answer:
A. The tendency of the atom to pull on electrons
Explanation:
Took the quiz for A⃣ p⃣ e⃣ x⃣ , its A
got the answer, so in other words, I'm good.
Answer:
Brainliest?
Explanation:
pls!!!!!
GIVING BRAINLIEST!
What kinds of observations can you make that might indicate a chemical change is taking place?
Color Change.
Production of an odor.
Change of Temperature.
Evolution of a gas (formation of bubbles)
Precipitate (formation of a solid)
Hope this helps!:)
Which groups on the periodic table represent the s- block ?
Answer:
Groups 1 and 2.
Explanation:
The elements of Group 1 and Group 2 of the modern periodic table are called S block elements. The two types of s block elements are possible i.e. the elements with one electron (s1) or the elements with two electrons (s2) in their s-subshell.
How many sp2 and sp3 are in caffeine?
Answer:
5.56×10²² molecules of AlPO4
Explanation:
i think thats is the correct answer if its wrong im really sorry
An average human body has 84.0 g of chlorine (as chloride ions) in it. If the average mass of a human body is 70.0 kg, what is the concentration of chlorine in ppth?
Answer:
[tex]ppth=1.2ppth[/tex]
Explanation:
Hello!
In this case, since the parts per thousand of a solute in a solute is defined in terms of its grams per kilogram of solution (unlike parts per million which are mg/kg) we can mathematically represent it via:
[tex]ppth=\frac{grams_{solute}}{kg{solution}}[/tex]
Now, since the whole human body acts as the solution and the chlorine in the form of ions as the solute, the required ppth turns out:
[tex]ppth=\frac{84.0g}{70.0kg}\\\\ppth=1.2ppth[/tex]
Best regards!
Water contains 2 polar bonds and the molecule is polar
True
False
HELPPP
1. If 4,500 joules of heat are emitted when a sample of water freezes, what is the mass of the water? And is it endothermic or exothermic
2. Calculate the number of grams of ice, at 0.0 ºC, that could melt if 3.6 kJ of heat were added. And is it endothermic or exothermic
3. Find the number of grams of vapor that condense into 373 K when 17.2 kJ of heat is removed. And is it endothermic or exothermic
1 endothermic 2 yes and exothermic 3 endothermic
which type of experiment follows ethical standars?
A.Releasing contaminated waste into water system?
b. perfoming test on animals when the information can be obtained in other ways?
c. doing research on animals in which the animal experiences to fear or pain.
d. perfoming tests on people who cannot protect themselfs?
Answer:
A.Realesing contaminated waste into the water system
Explanation:
because if you you try it would really work
Please Help. A car was sitting in sunlight all day long.The heat that is now contained in the car was transferred to the car primarily by which of the following processes?
A. Radiation
B. Conduction
C. Convection
D. Electrical energy transfer
Answer: A
Explanation:
The heat contained in the car was transferred to the car primarily by the process of radiation.
Radiation is the emission of electromagnetic wave energy that originates from a source and travels via a space medium with the speed of light. When it is sunny during the day, all life forms and inanimate objects are exposed to radiation. Since a car has metallic properties, it has the ability to store and contain the heat for a longer period of time through the process known as radiation.
Learn more about radiation here:
https://brainly.com/question/12494464?referrer=searchResults
Why is the area called the Fertile Crescent?
Answer:
the soil is very fertile
Explanation:
When you bite into an apple, your teeth act as which type of simple machine?
Answer:
Lever.
Hope this helps!
Explanation:
Answer:
Wedge
Explanation:
The simple machine that SPLITS the apple when you bite into it is a wedge.
What is the coefficient for titanium tetrachloride when the equation below is balanced?
TiCl4 + H2O TiO2 + HCl
a. 4
b. 1
c. 2
d. 3
Answer:
I believe that it is B. 1
Explanation: I could be wrong but I believe its 1
Which of the following is always altered when a substance undergoes a
chemical change?
a- state of matter of the substance
b- color of the substance
c- mass of the substance
d- arrangement of the atoms composing the substance
color of the substance
State the type of stability of Cl- ion.
Which root word of the binary ionic compound ends with -ide?
The metal
The positive ion
The non-metal
The group 1 element
Answer: the non metal
Explanation:
in a closed system as the temperature of a liquid increases the vapor pressure of the liquid
If a compound pulley has four
rope segments pulling up on the
load, by what factor does it
multiply the force applied to the
pulley?
Answer:
With four rope segments, the ideal mechanical advantage is 4. This means that the compound pulley multiplies the force applied to it by a factor of 4.
Explanation:
Which term is the rate at which work is done
Answer:
1
Explanation:
7: How many times can a cell divide?
Explanation:
60 times and it matters why they need to in order to divide