Answer:
30
Explanation:
use the keep,change,change method.
19 + 11
19,keep, "-" change to addition, -11,change to positive
now use this
19 + 11 = (30 )
11) When sodium metal is subjected to violet light, it causes the photoelectric effect. However, red light does not affect
the sodium. Explain this phenomena.
The phenomena in which violet light causes photoelectric effect and red light does not is because red light does not achieve the minimum frequency for the phenomenon to occur but violet light does.
The phenomenon in which a substance emits electrons when light is incident upon it is called the photoelectric effect.
This electron would not be emitted if the frequency of the light does not exceed a minimum frequency called the threshold frequency.
Since in the case of the sodium metal, violet light causes the photoelectric effect while red light does not.
This implies that red light does not exceed the minimum frequency for the photoelectric effect to occur, but violet light does thereby causing the photoelectric effect to occur.
So, the phenomena in which violet light causes photoelectric effect and red light does not is because red light does not achieve the minimum frequency for the phenomenon to occur but violet light does.
Learn more about photoelectric effect here:
https://brainly.com/question/19744165
4. What is a common cause of acid rain?
Answer:
Exhaust from cars, trucks, and buses releases nitrogen oxides and sulfur dioxide into the air. These can cause acid rain.
Hope this helps! :)
HELPPPPPPPPPPPPPPPPPPPPPPPP
What is the difference between a producer and a consumer? (Select all that apply.)
Consumers can make their own food energy and producers cannot.
Producers convert sunlight energy into fuel and consumers cannot.
Consumers convert sunlight energy into fuel and producers cannot.
Producers can make their own food energy and consumers cannot.
Answer:
producers convery sunlight energy into fuel and consumers cannot
producers can make their own food energy and consumers cannot
Which has the greatest electronegativity?
Copper 11 oxide and charcoal are black solids . How would you distinguish between the two solids
Element X is in group 2, and element Y is in group 7, of the periodic table. which ions will be present in the compound formed when X and Y react together?
A) X^+ and Y^-
B)X^2+ and Y^-
C)X^+ and Y^2-
D)X^2- and Y^+
Answer:
Element X has valency 2 while Y Valency 2, element Y has high tendency of gaining electrons for its stability thus the compound formed will be B
elements X is positively charged while Y will be negatively charged
The groups or the families in the periodic table are denoted by the vertical column. Element in group 2 and 7 forms compound with ions X²⁺ and Y⁻. Thus, option B is correct.
What is the periodic group?A group of the periodic table is also called a family that has the elements placed togther with the same number of the valence electron. Group II has two valence electrons and VII has seven valence electrons in the outer shells.
The two valence electrons of the atom can be donated easily compared to acquiring the six electrons to complete the octet and stability. Similarly, the seven valence electrons are hard to donate but can accept one electron to achieve satbility.
The group II element X will donate its two electrons to acquire a +2 charge, whereas group VII element Y will accept one electron and acquire a -1 charge.
Therefore, option B. X²⁺ and Y⁻ presents the ions of the compound.
Learn more about groups here:
https://brainly.com/question/15098014
#SPJ2
Explain why the structure of Copper [ 1s², 2s², 2p⁶, 3s², 3p⁶, 3d¹⁰,4s¹] is more stable than [ 1s², 2s², 2p⁶, 3s, 3p²⁶, 3d⁹,4s² ].
A subshell which is 100% full or 50% full is more stable than subshells which are partially filled with a number of electrons less than or greater than half the number of electrons which can be held by the subshell.
Explanation:
What is a solvent? please answer
A. The material that is dissolved
B. The material that increases the speed of the dissolution
C. The material that reduces how much can be dissolved
D. The material that is dissolving another material
WILL MARK BRAINLIEST
Answer:
D
Explanation:
Solvent is the material that is dissolving another material. Thus, option D is correct.
A solvent is a substance that dissolves another substance to form a solution. The substance that is being dissolved is called the solute, and the substance that is doing the dissolving is called the solvent. The solute is usually present in a smaller amount than the solvent, and it is the solvent that determines the physical properties of the solution, such as its density, viscosity, and boiling point.
For example, when salt is dissolved in water, the salt is the solute and the water is the solvent. The water molecules surround the salt molecules and break them apart, so that the salt ions are free to move around in the solution. The solution is then a homogeneous mixture of salt ions and water molecules.
Thus, option D is correct.
Learn more about solvent on:
https://brainly.com/question/11985826
#SPJ3
A chemist measured the temperature of a liquid to be 26 ∘C, then she heated the liquid to 83 ∘C. By how many Kelvins did the temperature change.
Answer: 57.C
Explanation: simple subtraction
which of the following are physical properties of nonmentals
You did not provide any options.
A mystery element has 18 protons. Which one of the following statements is true about the element?
a.The element belongs in row 2 of the periodic table and is classified as a halogen.
b.The element belongs in row 3 of the periodic table and is classified as a noble gas.
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:
its aragon , so letter b is right
Explanation:
plesse hurry aand help with QQQQQ
Answer: the answer should be A the first one
plzz give me brainliest
What happens during liquefaction?
Answer:
it becomes water of it liqud
Explanation:
il explain in comment if you brainly me
give the symbol and the nuclei number of an isotope that is used as a nuclear fuel
Answer: The nuclear symbol of an isotope indicates the number of protons and neutrons in an atom of the element. It does not indicate the number of electrons. The number of neutrons is not stated. Instead, you have to figure it out based on the number of protons or atomic number.
Explanation:
brain me
An isotope of nitrogen experiences the weak force which transforms one of its
protons to a neutron. How would this change the atom?
Select one:
O a. It would have no effect because nitrogen still has the same mass
number.
O b. It would transform the nitrogen atom to a carbon atom.
It would make the atom transform it into a heavier isotope of nitrogen.
O d. It would transform nitrogen to an oxygen atom.
Check
Answer:
It would transform the nitrogen atom to a carbon atom
Explanation:
Graphite conducts heat in a similar way to metals because it contains __________ __________. What two words complete the sentence?
Answer:
Free electrons
Explanation:
Graphite conducts heat in a similar way to metals because it contains free electrons.
Conductivity is arised from the delocalization of free electrons. Metals are electron rich and conduct thermally and electrically. Graphite conducts heat in a similar way because it contain delocalized electrons.
What is graphite?Graphite is an allotrope of carbon as diamond and fullerenes. Graphite exhibits a layered helical structures in which the carbon atoms are arranged in a hexagonal fashion.
Substances conduct electricity and heat when they are rich in electrons and are mobile to pass through it. Metals are electropositive and they contains extra electrons which can be delocalized between orbitals or energy levels.
This delocalization of electrons results in an a thermal or electrical current in the substance. Carbon is in sp2 hybridisation in graphite. Where, the electrons can transit from one layer to the other in the layered structure.
Therefore, the presence of delocalized electrons make graphite conducting.
To find more on graphite, refer here:
https://brainly.com/question/29020014
#SPJ2
in space why is it black in space except the planets
Answer:
because space is near-perfect vacuum - meaning it has exceedingly few particles- there is virtually nothing in the space between stars and planets to scatter light to our eyes
5 example of similarities between compression and tension stress?
Answer:
Mark me as Brainliest please
Explanation:
Compression vs Tension
Tension and compression are two concepts discussed in physics. Tension is a force, while compression is a phenomenon. Both these concepts play important parts in fields such as mechanical systems, automobile engineering, heat engines, material science, pendulums and various other fields. It is vital to have a proper understanding in tension and compression in order to excel in such fields. In this article, we are going to discuss what compression and tension are, their definitions, applications of compression and tension, the similarities between compression and tension and finally, the difference between compression and tension.
I need help with the question below
Answer:
D po
Explanation:
Sana nakatutulong
#Carry on learning
Pa brainliest po
determine whether each phrase describes starch, glycogen, or cellulose.
Answer:
Starch is a soft, white, tasteless powder that is insoluble in cold water, alcohol, or other solvents.
glycogen is a substance deposited in bodily tissues as a store of carbohydrates. It is a polysaccharide which forms glucose on hydrolysis.
Cellulose is a molecule, consisting of hundreds and sometimes even thousands of carbon, hydrogen and oxygen atoms.
PLEASEEE ANSWER PLEASEEE PLEASE I’ll mark brainliest
Answer:
Lithium has 1 valence electron, Sulfur has 6
A is oxidized, B is reduced
A is reducing agent, B is oxidizing agent
Explanation:
when an atom loses electrons, it is oxidized
when an atom gains electrons, it is reduced (almost think of when you add a negative number to a positive number, the positive number gets smaller or is reduced)
Put the sets of 3 elements in order from least metallic character to most metallic character. Help please!!
Answer:
29:Mn,V,Sr
30:Ni,Pd,Cs
31:Cr, Mo, W
32:Sn,Pb,Ti
33:F, P, As
Sorry I was in a rush so it may not be right; so check with this picture to help you out.
Figure 5 shows how the temperature of a substance changed as it was heated. Which segment of the graph indicates that the substance was undergoing a change of state?
answer:
B
Why:
Because when heated up, the particles vibrate from the heat and keep on vibrating.
at point b of the diagram, the energy is gone to breaking bonds of the (let's assume) solid.
So there is no change in temperature.
I hope this helps please let me know if you need me to explain more.
When temperature is changing with respect to the time in the given graph, then substance B was undergoing a change of state.
What is change of state?When any substance converts from one form of matter to the other form, then this phenomenon is known as change of state.
In the given figure a graph represents the change in temperature of substances A, B, C and D with respect to the time. Temperature of the substances A, C & D keep continuous changing with respect to the time. But substance B shows change in state because it absorbs the heat to convert in another state by breaking old bonds and making new bonds and showing showing no change in temperature.
Hence, substance B was undergoing a change of state.
To know more about change of state, visit the below link:
https://brainly.com/question/2569418
Which one of the following is an example of extensive
property?
a Hardiness
be Density
a Meliting point
d. Electrical resistance
Clear my choice
Answer:c
Explanation:
Answer:
mass an volume or hardines be density
A student draws a model of one of the sun's layers. The student draws arrows to represent hot gas moving away from the center of the sun and other arrows to represent cool gas moving toward the center of the sun. Which layer does the model show?
Radiation Zone
Convection Zone
Chromosphere
Inner Core
Answer:
The convection zone :)
What is acid rainnnnnn
Answer:
ACID RAIN
Explanation:
duh
What is an activation energy
Answer:
Defination of Activation energy :- In chemistry and physics, activation energy is the minimum amount of energy that must be provided for compounds to result in a chemical reaction. The activation energy of a reaction is measured in joules per mole, kilojoules per mole or kilocalories per mole. Meaning of Activation energy :- The minimum quantity of energy which the reacting species must possess in order to undergo a specified reaction.Explanation:
Hope this helps you dear ✌️Carry on learning !!Do all particles pass right through the atoms undeflected?
Answer:
no when Rutherford performed the gold foil experiment he bombard the atom alpha particles and two other scientist, Geiger and Marsden came with great news saying the particles suffered serious deflection
Why is knowledge of the activity series crucial in choosing which metal to build things with?
Answer:
activity series is a list of substances ranked in order of relative reactivity.
For example, magnesium metal can displace hydrogen ions from solution. So magnesium is more reactive than hydrogen:
Mg(s) + 2H⁺(aq) → H₂(g) + Mg²⁺(aq)
Zinc metal can also displace hydrogen ions from solution:
Zn(s) + 2H⁺(aq) → H₂(g) + Zn²⁺(aq)
so zinc is also more active than hydrogen.
But magnesium metal can displace zinc ions from solution:
Mg(s) + Zn²⁺(aq) → Zn(s) + Mg²⁺(aq)
so magnesium is more active than zinc.
The activity series including these elements would be Mg > Zn > H.
Chemists have built up a complete activity series in a similar way.
The most active metals are at the top of the table; the least active are at the bottom.
Any metal that is higher in the series will displace a metal that is below it in a
The knowledge of the activity series in choosing which metal to build things with because; it provides a basis for determining which metal ion is able to displace the other upon chemical interaction.
The choice of building material is a very important design consideration.
This is so because careful consideration must be taken while deciding which metal to build things with as the reactivity of metals vary.This variation is carefully quantified by the position of metals on the activity series.
Read more;
https://brainly.com/question/17597543
Copernicus believed the planetary motions were due to:
Answer:circular heliocentric orbits.
Explanation:
