Answer:
Radio waves were first developed in WWII
Explanation:
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Question 21 of 25
Which of the following are elements in this equation:
2Mg(s) + O2 (9) ► 2Mgo (s)?
Check all that apply.
A. g
B. Mg
C. O
D. S
Answer: Mg and O
Explanation: just took the test. Trust
please helpppp!!!!!!!!!!!
Answer:
If a substance can be dissolved it is called soluble.
if a substance cannot be dissolved it is called insoluble
this process is called..
Answer:condensation
Condination
Explanation:
what do mars, pluto, and Jupiter have in common (science) in 8th grade.
Answer:
they are all planets
Explanation:
Based on information from the periodic table, which statement is true for the
element cobalt?
Answer: (A) a cobalt atom contains 27 protons, and most cobalt atoms contain 32 neutrons.
Explanation: just answered the question and that was the correct answer
Answer: The answer is : A cobalt atom contains 27 protons and MOST neutral cobalt atoms contain 32 electrons
Explanation: I took the test
Which statement is correct about the rate of chemical reactions? (5 points) It increases when the temperature decreases. It increases when a catalyst is added. It does not depend on the temperature. It does not depend on the presence of catalysts.
There is an increase in temperature when the rate of chemical reactions increases.
What is a chemical reaction?The chemical reaction is the process in which the two or more substances where the reactions are converted into one or more different substances. These may be either chemical elements or compounds.
The chemical reaction rearranges the atoms of the reactants to create the different substances of the product. The speed of the reaction depends on the rate of temperature and as well reactant itself.
Find out more information about the chemical reactions.
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Answer:
It increases when a catalyst is added.
Explanation:
"A catalyst is a substance that can be added to a reaction to increase the reaction rate without getting consumed in the process. Catalysts typically speed up a reaction by reducing the activation energy or changing the reaction mechanism." (Khan Academy)
Students studying solid-state
physics are discussing the
microscopic structure of
materials.
Which student's statement
correctly identifies the nature
of these materials?
Answer:Material X would be classified as a crystalline solid because atoms are in a highly ordered three-dimensional arrangement.
Explanation: it makes sense I'm sorry if its wrong
Help please help me!!!!!
Answer:
B. 460 NM
Explanation:
THAT THE ANSWER
!!!!!!!!!!!HELPPPP!!!!!!!!!!! IT'S A TEST!
A forest fire began when lightning struck a tree.
A. Describe this type of reaction as either a chemical or physical reaction? Why?
B. Is the reaction endothermic of exothermic? Why?
2. What states of matter exist within the human body? What state of matter do you think your body is mostly made up of? Why? (4 points) Think about whether the body contains solids, liquids, or gases. Which of the three would you be most likely to find?
Answer:
Solids, liquids, and gases, exist in the human body. The body is mostly made up of liquid because the human body is 60% water. You would most likely be able to find solids (bones), liquids (blood, stomach acid) and gases (oxygen in your lungs or air in your digestive tract).
Explanation:
Ionic compounds are held together with ionic bonds between ions. The ions are formed when valence electrons are
Answer: Electrovalent bonds are produced when electrons are transferred from atoms of one element to atoms of another element, producing positive and negative ions. The bond which is formed by the transfer of electrons between the atoms is called electrovalent bond or ionic bond. Electrovalent bonds are only formed between metals and non-metals. Electrovalent bonds are not formed between two non-metals.
In simple words electrovalent bond involves the transference of a certain number of electrons to another dissimilar atom which has a tendency to gain electrons so that both acquire stable inert gas configurations. The electrostatic attraction always tends to decrease the potential energy. Hence, the potential energy of the system is much less than it was before the formation of an ionic bond.
Explanation: An Ionic bond is the bond formed by the complete transfer of valence electron to attain stability.
This type of bonding leads to the formation of two oppositely charged ions – positive ion known as cations and negative ions are known as anions.
The presence of two oppositely charged ions results in a strong attractive force between them. This force is an ionic or electrovalent bond.
Ionic bonds form between atoms with large differences in electronegativity, whereas covalent bonds formed between atoms with smaller differences in electronegativity.
The compound formed by the electrostatic attraction of positive and negative ions is called an ionic compound.
1 Clouds are formed when millions of drops of water become suspended in the air. Which
of the following is a step in the process of cloud formation?
A Expansion of cold air
B Formation of carbon dioxide
C Condensation of water vapor
D Breakdown of atmospheric ozone
Answer:
C Condensation of water vapor
Explanation:
One of the components of the atmosphere is water vapour. Water vapour is always present in air.
This water vapour may combine with particles of dust and smoke and condense around them to form clouds.
As more water vapour condenses and coalesces, the clouds become thicker and precipitation eventually follows.
6. If the pressure of a gas is 1.01 atm and the temperature is 25°C, then if the pressure is increased to 1.10, what is the new temperature?
Answer:
324.554 K
Explanation:
Which can be converted back to °C by subtracting 273
Once again thus answer can be found using the gas law P1/T1 =P2/T2
Remember to convert to Kelvin before doing the calculations by adding 273
During Photosynthesis, what does a producer take in from the air?
How many moles of aluminum are in 54 grams
Which of the following statements describes a REACTANT and where they are
chemical equation?
The chemicals that
you begin with, found
on the right side of the
equation
The chemicals that The chemicals that The chemicals that
you begin with, found end with, found on the you enyi with, found or
on the left side of the left side of the the right side of the
equation
equation
equation
Music of
Answer: The statement, chemicals that you begin with found on the left side of the equation, describes reactant and where they are in a chemical equation.
Explanation:
An equation that includes symbolic formulas and represents chemical reaction between the substances initially present forming new substances is called a chemical equation.
For example, [tex]N_{2} + 3H_{2} \rightarrow 2NH_{3}[/tex]
Here, substances [tex]N_{2}[/tex] and [tex]H_{2}[/tex] are the reactants. Reactants in a chemical equation are always present on the left side as these are the chemicals we begin with.
Also here, [tex]NH_{3}[/tex] is the product. Product(s) in a chemical equation are always present on the right side as these are the chemicals we end with.
Thus, we can conclude that the statement, chemicals that you begin with found on the left side of the equation, describes reactant and where they are in a chemical equation.
What is the mass number of an element?
I need help on deciding which one i should get
Answer:
I would say the purple one!
Explanation:
Which of the following an ionic bond like what holds Na+ and Cl- together in NaCl?
(Hint: Ionic bonds form between metals & non-metals.)
a
The chemical bond that holds H+ and N3- together in NH3
b
The chemical bond that holds Be2+ and Cl- together in BeCl2
c
The chemical bond that holds B3+ and Cl- together in BCl3
d
The chemical bond that holds H+ and Cl- together in HCl
Answer:
Rb
Explanation:
Rb look closely
1.How many moles of each element are in 0.0250 mol of K 2 Cr O 4?
2. How many moles of ammonium ions are in 4.50 mol of (N H 4 ) 2 CO 3 ?
Please explain with all the process and answers
Answer:
1. In 0.0250 moles of potassium chromate there are 0.05 moles of potassium , 0.025 moles of chromium and 0.1 moles of oxygen are present.
2. In 4.50 moles of ammonium carbonate there are 9 moles of ammonium ions and 4.5 moles of carbonate ions are present.
Explanation:
1.
Moles of potassium chromate = 0.0250 mol
Formula of potassium chromate = [tex]K_2CrO_4[/tex]
1 mole of potassium chromate has 2 moles of potassium , 1 mole of chromium and 4 moles of oxygen.
Then in 0.0250 moles of potassium chromate:
Moles of potassium will be:
[tex]2\times 0.0250 mol= 0.05 mol[/tex]
Moles of chromium will be:
[tex]1\times 0.0250 mol= 0.025 mol[/tex]
Moles of oxygen will be:
[tex]4\times 0.0250 mol= 0.1 mol[/tex]
2.
Moles of ammonium carbonate = 4.50 mol
Formula of ammonium carbonate =[tex](NH_4)_2CO_3[/tex]
1 mole of ammonium carbonate has 2 moles of ammonium ion and 1 mole of carbonate ion.
Then in 4.50 moles of ammonium carbonate:
Moles of ammonium ion will be:
[tex]2\times 4.50 mol= 9mol[/tex]
Moles of carbonate ions will be:
[tex]1\times 4.50 mol= 4.5 mol[/tex]
Describe all the relationships between pressure, volume, and
temperature
Answer:
volume is how much an object can hold, pressure is the force the pushes things into the center, and temperature, if extreme heat can cause pressure. and volume of an object can hold certain amounts of pressure from temperature.
Explanation:
If a solution has a [H+] of 9.3x10-11, what is the pH?
Answer:
10.03Explanation:
The pH of a solution can be found by using the formula
[tex]pH = - log [ {H}^{+} ][/tex]
From the question we have
[tex]ph = - log(9.3 \times {10}^{ - 11} ) \\ = 10.0315...[/tex]
We have the final answer as
10.03Hope this helps you
When bacteria have multiplied at least 1000 times, what is the pattern of growth that can be seen with the naked eye is called?
cluster
colony
family
clump
Answer:
Colony
Explanation:
Which of the following best describes a binary compound?
I. It is always made up of a metal and a nonmetal.
II. It always ends with -ide.
III. It always uses the Greek prefixes.
Answer:
metal and nonmetal it always include
-
(11) Deduce the number of dyes in food colouring H.
(iii) Suggest why food colouring F does not move during the experiment.
(iv) Explain which two food colourings contain the dye that is likely to be the most soluble the solvent.
(b) Determine which food colouring contains a dye with R, value closest to 0.67
Show your working.
Answer:
(ii) 1 dye
(iii) Food coloring F is insoluble in the solvent
(iv) 'E' and 'H'
(b) Food colouring G
Explanation:
Paper chromatography principle is based on the rates of migration of chemicals across a sheet of paper which are different and it consists of a stationary phase such as the water in the paper and a mobile phase such as the solvent resulting in the partitioning of the components of the mixture across the paper
The solution components are positioned to start in one place from where they migrate and separate out on the chromatography paper
(ii) The number of components into which the food colouring 'H' separates into = 1
Therefore, the number of dyes in food colouring 'H' = 1 dye
(iii) Food coloring 'F' does not move because it is insoluble in the solvent, which is the mobile phase
(iv) The food colouring that contains the dye that is likely to be most soluble in the solvent are does for which the dyes travel furthest, which are;
Food coloring 'E' and 'H'
(b) Using a similar question solution found on 'tutor my self' website, we have;
The [tex]R_f[/tex] values are given as follows;
[tex]R_f = \dfrac{Distance \ moved \ by \ dye}{Distance \ moved \ by \ solvent}[/tex]
The distance moved by the solvent = 5 units
The distance moved by dyes in food colouring 'E' and 'H' = 4 units
The distance moved by dye in food colouring 'G' = 3.3 units
The distance moved by the second dye in food colouring 'E' = 2.7 units
By inspection, we get;
[tex]R_f[/tex] dye in food colouring 'G' = 3.3/5 = 0.66,
Therefore, the dye with [tex]R_f[/tex] value closest to 0.67 is the dye in food colouring 'G'.
Which of the following would be the best caption for this image?
A
The Coriolis effect causes convection cells of air to circulate through the atmosphere.
B
The pattern of ocean currents is identical to the pattern of wind currents.
C
Uneven heating of land and water causes winds to blow in different directions during the daytime and night time.
D
There are six bands of global wind currents. These bands of wind currents are caused by convection cells created by the warming and cooling of air.
5. What is the difference between a reflected and a diffracted sound wave?
A. A reflected sound wave is absorbed by the medium. A diffracted sound wave changes
direction as it passes through an opening.
B. A diffracted sound wave bounces back to the place of origin. A reflected sound wave is
absorbed as it passes through an opening.
C. A reflected sound wave bounces back to the place of origin. A diffracted sound wave
changes direction as it passes through an opening.
D. A diffracted sound wave bounces back to the place of origin. A reflected sound wave
changes direction as it passes through an opening.
Answer:
Reflection involves a change in direction of waves when they bounce off a barrier; refraction of waves involves a change in the direction of waves as they pass from one medium to another; and diffraction involves a change in direction of waves as they pass through an opening or around a barrier in their path.
Explanation:
https://www.physicsclassroom.com/class/waves/Lesson-3/Reflection,-Refraction,-and-Diffraction#:~:text=Diffraction%20of%20Waves-,Reflection%20involves%20a%20change%20in%20direction%20of%20waves%20when%20they,a%20barrier%20in%20their%20path.
Reflection of sound wave differs from diffraction of sound wave in that a reflected sound wave bounces back to the place of origin while a diffracted sound wave changes direction as it passes through an opening.
What is reflection?Reflection is the bouncing back of a wave when it hits an obstacle along its path.
What is diffraction?Diffraction is the spreading out of a wave in a circular path as it passes through a tiny opening.
Therefore, the difference between reflection and diffraction is that a reflected sound wave bounces back to the place of origin while a diffracted sound wave changes direction as it passes through an opening.
Learn more about reflection and diffraction at: https://brainly.com/question/11176463
A gas has a volume of 45.0 mL and a pressure of .98 atm. If the pressure increased to 2.1 atm and the temperature remained the same, what would be the new volume?
Answer: The new volume is 95.45 mL.
Explanation:
Given: [tex]V_{1}[/tex] = 45.0 mL, [tex]P_{1}[/tex] = 0.98 atm
[tex]P_{2}[/tex] = 2.1 atm, [tex]V_{2}[/tex] = ?
According to Boyle's law, at constant temperature the pressure of a gas is inversely proportional to its volume.
Therefore, formula used to calculate the new volume is as follows.
[tex]\frac{P_{1}}{V_{1}} = \frac{P_{2}}{V_{2}}[/tex]
Substitute the values into above formula as follows.
[tex]\frac{P_{1}}{V_{1}} = \frac{P_{2}}{V_{2}}\\\frac{0.98 atm}{45.0 mL} = \frac{2.1 atm}{V_{2}}\\V_{2} = 95.45 mL[/tex]
Thus, we can conclude that the new volume is 95.45 mL.
Which of the following statements are true? Select all that apply. Check All That Apply All isotopes of carbon (C) have the same number of protons. All isotopes of carbon (C) have the same number of protons. An atom with six protons in its nucleus will always have six neutrons in its nucleus. An atom with six protons in its nucleus will always have six neutrons in its nucleus. An atom with a neutral charge has an equal number of protons and electrons.An atom with a neutral charge has an equal number of protons and electrons. The mass number is the total number of electrons and protons in an atom. The mass number is the total number of electrons and protons in an atom.
Answer:
An atom with a neutral charge has an equal number of protons and electrons.
Explanation:
The three main subatomic particles in the atom are neutrons, protons and electrons.
Protons are positively charged particles, electrons are negatively charged particles while neutrons are not charged particles.
An atom is neutral if the number of protons and electrons are equal. This is the condition for neutrality in the atom.
The number of protons will be the same for all isotopes of Carbon. Options A and C are correct.
What made an atom?
An atom is made up of central nucleons (positive protons and neutral neutrons) and surrounding negatively charged electrons.
In a neutral atom, the number of electrons and protons is the same because opposite charges neutralize each other.
The number of protons is the same in all isotopes of an element because changing the proton changes the identity of the element.
Therefore, the number of protons will be the same for all isotopes of Carbon.
Learn more about atom:
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HELPPPPPP PLEASE
1. How many elements are in the formula?
2. How many atoms are in the formula?
3. How many compounds are in the formula?
4. How many oxygen atoms are in the formula?
5. What do coefficients tell you about a chemical formula? to show the
relative amounts of each substance present.
6. What do subscripts tell you about a chemical formula? the number of
atoms of the element immediately before the subscript.
7. Draw a picture of the formula.
Answer:
There are 3 elements, Sodium, Carbon, and oxygen. There are 2 Sodium atoms 2*2=4, one carbon, and 3 Oxygen so 4+1+3=8 total atoms. one compound CO3
Explanation:
that's all I know