Answer:
[tex]\boxed {\tt D. \ Hydrogen}[/tex]
Explanation:
An element has a uniform composition, cannot be broken down by chemical change, every atom has the same atomic number, and can be found on the Periodic Table.
Water is made of hydrogen and oxygen atoms (H₂O) so it is not an element.
Table salt is made of sodium and chloride atoms (NaCl) so it is not an element.
Iron oxide is made up of iron and oxygen atoms, so it is not an element.
Hydrogen is an element. It can be found on the Periodic Table as element H.
The correct answer is D. Hydrogen
The explosions that take place during a fireworks show are an example of which of the following? (2 points)
Image of fireworks exploding in air
Chemical change
Chemical property
Physical change
Physical property
Answer:
Chemical Change
Explanation:
The explosion of fireworks is an example of chemical change. During a chemical change, substances are changed into different substances. In another words, the composition of the substance changes.
What two elements fill their last electron in the 5s sublevel?
Answer:Rubidium and Strontium
Explanation:
How many protons are there in a neutral, stable Hydrogen atom that makes up 99.985% of the element?
A. 1
B.2
C.3
D.4
E.0
Which statement is not
true?
A. Protons are positive and neutrons are
neutral
B. Electrons have the most mass of the
subatomic particles
C. Protons and Neutrons are found in the
nucleus
Electrons are found outside the nucleus
and have a negative charge
Answer:
B. Electrons have the most mass of the
subatomic particles
Compared to the mass of neutron and proton, mass of electron is negligible.
Answer:
B
Explanation:
when creating a Bohr model, you will usually mark protons + or P and neutrons are usually 0 or N.
Electrons are on the rings surrounding the nucleus, but everything else is inside.
Electrons are typically represented by - or E
A 5 kg block
is pulled across a table by a horizontal force of 4O N with a frictional force ot 8N pOsing the motion. Calculate the acceleration of the oject. 12 An ahia iddt
Answer:
By Newton's 2nd law, m*a=sum_of_forces where m is the mass and a the acceleration. Here there are two forces in opposed directions.
Thus 5*a=40-8=32 therefore a=32/5=6.4m^s/2
Write the half reactions and the balanced equation for the galvanic cell Cu(s)| Cu2+(aq)|| Cu+(aq)| Cu(s). What is the smallest possible integer coefficient of Cu+(aq) in the combined balanced equation?
Answer and Explanation:
The galvanic cell is:
Cu(s)| Cu²⁺(aq)|| Cu⁺(aq)| Cu(s)
The first two species before the double bar (||) constitute the anodic half reaction (oxidation):
Cu(s) ⇒ Cu²⁺(aq) + 2 e-
The two species after the || constitute the cathodic half reaction (reduction):
Cu⁺(aq) + e- ⇒ Cu(s)
If we multiply the reduction half reaction by 2 (to obtain the same number of electrons than oxidation reaction) and then we add the two half reactions, we obtan the balanced equation:
Reduction (cathode) : 2Cu⁺(aq) +2 e- ⇒ 2Cu(s)
Oxidation (anode) : Cu(s) ⇒ Cu²⁺(aq) + 2 e-
------------------------------------
Total equation: 2Cu⁺(aq) + Cu(s) ⇒ 2Cu(s) + Cu²⁺(aq)
Cu(s) is in both reactants side and products side, so we cancel that in both opposite sides to obtain:
2Cu⁺(aq) ⇒ Cu(s) + Cu²⁺(aq)
If we divide the balanced equation into 2, the smallest possible integer coefficient for Cu⁺(aq) is 1:
Cu⁺(aq) ⇒ 1/2 Cu(s) + 1/2 Cu²⁺(aq)
HELP PLEASE!!!
chemistry question
Answer:
Its going to be D) In sigma bonds the electrons are in the space between the joined atoms and pi bonds above and below the joined atoms
Any one know the answer?
[tex]1 \: mol MgSO4 \: has \: 4 \: oxygens[/tex]
Thus ;
[tex]2 \: mols \: of \: should \: have \: 8 \: oxygens[/tex]
So the correct answer is (( 8 مول ))
How much energy is required to heat 0.24 KG lutetium from 296.2K to 373.5 K? The specific heat for lutetium is 0.154 J/g-K
Answer:D. 2857 joules
Explanation:
Not going to lie I guessed but got it right
According to specific heat capacity, 3596.208 joules of energy is required to heat 0.24 kg of lutetium from 296.2 K to 373.5 K.
What is specific heat capacity?Specific heat capacity is defined as the amount of energy required to raise the temperature of one gram of substance by one degree Celsius. It has units of calories or joules per gram per degree Celsius.
It varies with temperature and is different for each state of matter. Water in the liquid form has the highest specific heat capacity among all common substances .Specific heat capacity of a substance is infinite as it undergoes phase transition ,it is highest for gases and can rise if the gas is allowed to expand.
It is given by the formula ,
Q=mcΔT
Substitution in above formula gives, q= 0.24×154×97.3=3596.208 Joules.
Thus, 3596.208 joules of energy is required to heat 0.24 kg of lutetium from 296.2 K to 373.5 K.
Learn more about specific heat capacity,here:
https://brainly.com/question/1747943
#SPJ2
Luciana explains to Eric how electricity flows in a circuit. Which sentences are a part of her explanation? Select all that apply.
A. Without a resistor, electricity cannot flow in a circuit.
B. Without a switch, electricity cannot flow in a circuit.
C. For electricity to flow in a circuit, the circuit must be complete.
D. An insulator such as plastic is needed for electricity to flow in a circuit.
E. A conductor is needed for electricity to flow in a circuit.
Answer:
E. A conductor is needed for electricity to flow in a circuit.
Explanation:
Electric current can flow without a resistor, as in short circuit.
A short circuit is an electrical circuit that allows a current to travel along an unintended path with no or very low electrical impedance.
Without a switch, electricity can flow in a circuit, switch is only used to close or open the circuit.
Thus, the only correct option is E
E. A conductor is needed for electricity to flow in a circuit.
Sodium has______ Valence electrons and bismuth has ________ electrons
Please help ASAP on market as brainlister
Answer:
Sodium has 1 valence electron and bismuth has 83 electrons (5 valence electrons)
Explanation:
Which body system is similar to the nucleus?
Answer:
the brain
Explanation:
Which of the following pairs of elements belong to the same period?
Answer:
He and Ar
Explanation:
Radioactive isotope X has a half-life of 500,000 years. This isotope may be found in some types of volcanic rocks. A particular sample of volcanic rock taken from a layer that covered up some of the earliest known human-like footprints contains 0.125 mg of isotope X. The volcanic rock sample originally contained 8.00 mg of isotope X. How long ago were these footprints made. I need the equation. Thanks. please I am stuck on this question. PLEASE
Answer:
The age of the earliest known human-like footprints is approximately 3000000 years.
Explanation:
Decay of isotopes is represented by the following ordinary differential equation:
[tex]\frac{dm}{dt} = -\frac{m}{\tau}[/tex] (Eq. 1)
Where:
[tex]\frac{dm}{dt}[/tex] - First derivative of mass with respect to time, measured in miligrams per year.
[tex]m[/tex] - Current mass of the isotope, measured in miligrams.
[tex]\tau[/tex] - Time constant, measured in years.
Now we proceed to obtain the solution of the differential equation:
[tex]\int\limits {\frac{dm}{m} } = -\frac{1}{\tau}\int dt[/tex]
[tex]\ln m = -\frac{t}{\tau}+C[/tex]
[tex]m(t) = e^{-\frac{t}{\tau}+C }[/tex]
[tex]m(t) = m_{o}\cdot e^{-\frac{t}{\tau} }[/tex] (Eq. 2)
Where:
[tex]m_{o}[/tex] - Initial mass of the isotope, measured in miligrams.
[tex]t[/tex] - Time, measured in years.
[tex]\tau[/tex] - Time constant, measured in years.
We proceed to clear time within the formula presented above:
[tex]\ln \frac{m(t)}{m_{o}} = -\frac{t}{\tau}[/tex]
[tex]t = -\tau \cdot \ln \frac{m(t)}{m_{o}}[/tex]
In addition, time constant can be found as a function of half-life:
[tex]\tau = \frac{t_{1/2}}{\ln 2}[/tex] (Eq. 3)
If we know that [tex]t_{1/2} = 500000\,yr[/tex], [tex]m_{o} = 8\,mg[/tex] and [tex]m(t) = 0.125\,mg[/tex], the age of the earliest known human-like footprints is:
[tex]\tau = \frac{500000\,yr}{\ln 2}[/tex]
[tex]\tau \approx 721347.520\,yr[/tex]
[tex]t = -(721347.520\,yr)\cdot \ln \left(\frac{0.125\,mg}{8\,mg} \right)[/tex]
[tex]t \approx 3000000\,yr[/tex]
The age of the earliest known human-like footprints is approximately 3000000 years.
2. Explain how energy originates and is emitted from a star.
Answer:
Stars generate energy through nuclear fusion. Here's an easy explanation about how the process works. ... Stars spend most of their lives repetitively compressing two hydrogen atoms into a single helium atom – plus a lot of energy, which is released as light and heat.
TIME REMAINING
58:36
The electron configuration for Helium (He) is shown below.
1s2
Which diagram shows the correct distribution of electrons in the electron shells of a helium atom?
Answer:
'*:*'
Explanation:
I know this looks weird, but
'= electron
*:* equals the nucleus, so 2 protons and 2 neutrons
and then '=electron
Which statement is the best description of a chemical bond?
O A. A chemical bond connects 2 different molecules.
B. A chemical bond holds atoms together.
C. A chemical bond turns molecules into atoms.
D. A chemical bond identifies atoms in a molecule.
The answer Is B;A chemical bond holds atoms together.
Which iron pot has the least thermal energy?
A. A5 kg pot at 130°C
B. A 2 kg pot at 120°C
C. A 5kg pot at 25°C
D. A 2 kg pot at 25°C
Answer: D. A 2 kg pot at 25C.
Explanation:
Can y’all look at this and help please
Answer:
2, 3, 4, 5
Explanation:
Pretty sure protons matter a lot unless in acid and bases but ignore this. Atoms mostly empty space as electrons are reeeeeeeeeeaaaallllllyyyy far apart. number of electrons change it is an ion and neutrons change pretty sure its an isotope. Electrons are stupidly small and fast so they don't really count towards the weight. Most mas comes from neutrons and protons in the nucleus
Answer:
2,3,4,5
1st is wrong cuz if u change the number of proton it would change the atomic number which results in different element
6th is wrong because most mass of the atoms come from neutrons and protons collectively so if it would have said THE ATOMS MASS MOSLTY COMES FROM NUCLEONS then u could mark it right
Gases ___ out and fill their container completely
Answer: Gases have the lowest density of the three, are highly compressible, and completely fill any container in which they are placed. Gases behave this way because their intermolecular forces are relatively weak, so their molecules are constantly moving independently of the other molecules present. Solids, in contrast, are relatively dense, rigid, and incompressible because their intermolecular forces are so strong that the molecules are essentially locked in place.
Explanation:
15
The correct formula for a compound formed from the elements Al and O is
a. AIO.
b. Al2O.
c. Al3O2-
d. AIO3.
e. Al2O3.
pleaseee help ASAP
will mark brainliest!!! <3
Answer:
it is C
Explanation:
I saw from Google. Hope it helps.
I cant get the full picture
sorry
Does Magnesium or Carbon have similar properties to Beryllium ? Which one ?
Answer:
Yes, Magnesium
In the human body, a series of chemical reactions results in the making of energy that is used at both the cellular and organismal levels.
In which course would a person most likely study these chemical reactions?
biochemistry
geochemistry
materials chemistry
physical chemistry
Answer:
It is A: biochemistry
Explanation: i seen there was no answer so i took a chance and surprisingly got it correct
Answer:
e correct option is all of the above
Explanation:
Selena is learning about how engineers choose metals for spacecraft. She discovers that spacecraft engineers often mix other metals with titanium. Titanium is a metal that is both lightweight and strong. It also resists corrosion. Selena wants to compare titanium with other metals. She looks at the cell from the periodic table that represents titanium.
Explain what each of the four items in the cell represents. Then, classify titanium as an alkali, alkali earth, or transition metal.
Ti is a transition metal.
Further explanationChemical symbol represent element or compound
The elements are arranged in the periodic system
1. 22This is the atomic number of Titanium
The Atomic Number (Z) indicates the number of protons of an element
2. TiThis is the symbol (chemical formula) of titanium
3. 47.90This is the mass number of Titanium
Mass Number (A) = Number of protons + Number of Neutrons
Atomic Number (Z) = Mass Number (A) - Number of Neutrons
4. TitaniumThis is the name of the element
To determine which group, alkaline, alkaline earth or transition it can be seen from the electron configuration
alkali and alkali earth : configuration from orbital 1s-7s
transition : configuration from orbital 3d-6d (Block d)
Electron configuration from Ti : [Ar] 3d²4s²
if we look at the configuration, then Ti is in the d block which is included in the transition metal
Answer:
The answer is 26
Explanation:
I just took the test
What group of organic compounds include starch?
a Carbohydrates
b Lipids
Thing
C Proteins
d Nucleic Acids
why does the uncertainty principle exist ?
Answer:
The uncertainty principle, proposed in 1927 by German physicist Werner Heisenberg, states that the more precisely a particle's position is measured, the less precisely its momentum can be known, and vice versa. ... They wanted to measure the polarization, or orientation, of the photon.
Which two models can be classified as elements
Answer:
First One And Third Pls Mark Brainlest
Explanation:
Which has the longest wavelength?
Which has the highest frequency?
Answer:
Which has the longest wavelength?
✔ microwaves
x infrared
x visible
x X-rays
Which has the highest frequency?
✔ X-rays
x infrared
x microwaves
x visible
Explanation:
I apologize if this was a late answer or if this doesn't answer your original question, but hope this helps! :)
Answer:
Microwaves then X rays
Explanation:
Perform the following metric conversions: Please explain bc I really dont get it at ALL !!!!
200.7 pm = _________________________nm
0.000357 hm = ______________________cm
14.78 mg = __________________________ g
8.280 μg = __________________________pg
Answer:
0.2007 nm
3.57 cm
0.01478 g
8280000 pg
Explanation:
1)200.7 pm
1 picometer is equal to 0.001 nanometer.
1 nm = 1000 pm
200.7 pm× 1 nm / 1000 pm = 0.2007 nm
2)0.000357 hm
1 hectometer is equal to 10,000 centimeter.
1 hc = 10,000 cm
0.000357 hc× 10,000 cm / 1 hc = 3.57 cm
3) 14.78 mg
1 gram is equal to 1000 milligram.
1 g = 1000 mg
14.78 mg × 1 g/1000 mg = 0.01478 g
4)8.280 µg
1 microgram is equal to 10⁶ picogram.
1 µg = 1000000 pg
8.280 µg× 10⁶ pg/ 1µg = 8.280×10⁶ pg or 8280000 pg