Answer:
24 hrs it takes for the earth to rotate
A student has two solid blocks that have different masses. The student knows that each block is composed of a pure substance, but she wants to know if the blocks are composed of the same pure substance. Which of these would best show that the blocks are composed of different substances?
A.
Both blocks can be scratched by a piece of glass.
B.
One block has a greater volume than the other block.
C.
Both blocks sink when placed in water.
D.
One block conducts electricity and the other does not.
Answer:
The answer is maybe B hope it helps
The substances which are made up of only one kind of particle and have a fixed or constant structure is defined as the pure substance. Here One block has a greater volume than the other block so that the blocks are composed of different substances. The correct option is B.
What is volume?The amount of space occupied by any three dimensional solid is known as the volume. These solids can be a cube, a cuboid, a cone, a cylinder or a sphere. It is simply how much space an object or substance takes up.
It is possible to have the volume without mass, such as an enclosed vacuum. The capacity of a container is not necessarily the same as its volume. It is the interior volume of a vessel. If you measure the exterior dimensions of the container, its volume is greater than its capacity.
Here the blocks are composed of different substances is indicated by the difference in the volume of the blocks.
Thus the correct option is B.
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2 questions. will give brainliest if i can figure out how
What happens to the electrons of a reducing agent during a reaction?
a.Electrons are gained
b.Electrons are lost
c.Electrons are held
d.Electrons are doubled
When is a substance reduced during an oxidation reduction reaction?
a.After one substance is oxidized
b.Before one substance is oxidized
c.Same time as one substance is being oxidized
d.Only oxidation occurs
1= b. electrons are lost
2= a. after one substance is oxidized
sub-atomic particles like negatively charged electrons, positively charged
protons and electrically ________ neutrons
Answer:
neutral
Explanation:
There are three basic subatomic particles. These are;
Protons (positively charged)Electrons (negatively charged)Neutrons (neutral)A neutron has no charge unlike the proton and the electron. It is present in the nucleus and contributes to the mass of the atom.
Describe reflection, refraction, and absorption.
Answer:
Refraction is the bending of a wave when it enters a medium where its speed is different, like going from the air (gas) to a glass of water (liquid). Absorption is when light energy penetrates an object. Typically this energy is then converted to heat.
seaborgium mass number =
Explanation:
seaborgium Is a type of corn that is grown in warm countries.
answer is SG
Answer:
269 u
Explanation:
These diagrams show two atoms of fluorine and an atom of magnesium.
On the left, a purple circle labeled F is shown twice, both times surrounded by 2 concentric circles. The inner circle has 2 small green spheres. The outer circle has 7 small green spheres. On the right, a purple circle labeled M g surrounded by 3 concentric circles. The inner circle has 2 small green spheres. The middle circle has 8 small green spheres. The outer circle has 1 small green sphere.
Which shows the correct steps in the formation of an ionic bond between these atoms?
A magnesium atom accepts six electrons from the fluorine atoms → Each fluorine atom donates three of the electrons → The magnesium atom becomes a -2 ion → Each fluorine atom becomes a +1 ion
A magnesium atom donates two electrons to the fluorine atoms → Each fluorine atom accepts one of the electrons → The magnesium atom becomes a -2 ion → Each fluorine atom becomes a +1 ion
A magnesium atom accepts two electrons from the fluorine atoms → Each fluorine atom donates one of the electrons → The magnesium atom becomes a -2 ion → Each fluorine atom becomes a +1 ion
A magnesium atom donates two electrons to the fluorine atoms → Each fluorine atom accepts one of the electrons → The magnesium atom becomes a +2 ion → Each fluorine atom becomes a -1 ion
Answer: D
Explanation:
took test
Answer:
D
Explanation:
got it right
. I am described as being conductive, malleable, shiny, and reactive with HCl. I am one of the most reactive elements. I turn black within seconds when I am exposed to air. If someone drops water on me, I will explode. When I do explode I send off characteristic purple-red (violet) flame. Who am I?
Answer:
Potassium
Explanation:
Most reactive metal in the reactivity series
The element in the question is referred to the alkali metal which is known as Potassium
Potassium is a highly reactive metal and reacts with Hydrochloric acid to
form a salt known as Potassium chloride and hydrogen gas.
Hcl + K ⇒ Kcl₍s₎ + H₂₍g₎
Potassium has a white color but when it reacts with water it explodes and
gives out a purple-red color as a result of the high excitation of electrons.
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What does a negative AH tell about a reaction?
A. The reaction absorbed heat.
B. The reaction has no enthalpy.
C. The reaction is exothermic.
D. The reaction is endothermic.
SUBMIT
Answer:
The reaction is exothermic
Explanation:
Pls help!
the chemical that is responsible for stopping reaction is called the ____
Answer:
reactant
Explanation:
I watched a chem video and this is what they called it.
What does it mean to dilute a solution?
Answer:
Dilution is the process of decreasing the concentration of a solute in a solution, usually simply by mixing with more solvent like adding more water to the solution
There are 4 mg of lead present in 2000 g of a water sample. What is the
concentration of lead in m?
Answer: 130 ppm Pb
Explanation:
We use parts per million to express the concentrations of solutions that contain very, very small amounts, often called trace amounts, of a given solute.
More specifically, a solution's concentration in parts per millions tells you the number of parts of solute present for every
10
6
=
1
,
000
,
000
parts of solution. You can thus say that a
1 ppm
solution will contain exactly
1 g
of solute for every
10
6
g
of solution.
In your case, you know that you have
38
mg Pb
⋅
1 g
10
3
mg
=
3.8
⋅
10
−
2
.
g Pb
in exactly
300.0 g
=
3.000
⋅
10
2
.
g solution
This means that you can use this known composition as a conversion factor to scale up the mass of the solution to
10
6
g
10
6
g solution
⋅
3.8
⋅
10
−
2
.
g Pb
3.000
⋅
10
2
g solution
=
130 g Pb
Since this represents the mass of lead present in exactly
10
6
g
of solution, you can say that the solution has a concentration of
concentration
ppm
=
130 ppm Pb
−−−−−−−−−−−−−−−−−−−−−−−−−−−−
The answer is rounded to two sig figs, the number of sig figs you have for the mass of lead present in the sample.
Magnesium oxide (mgo) has the rock salt crystal structure and a density of 3.58 g/cm3. the atomic weights of magnesium and oxygen are 24.31 g/mol and 16.00 g/mol, respectively. (a) determine the unit cell edge length.
Answer:
(a) The unit cell edge length 0.421 nm
Explanation:
Lets calculate -:
Given -
density = [tex]3.58g/cm^3[/tex]
Molecular weight of MgO = 24.31 +16
[tex]40.13 g/mole[/tex]
Avagadro number = [tex]6.022\times10^2^3[/tex]
In rock salt structure , there are four anions and four cations , hence Z=4 (Number of formula per unit cell)
Now, using the formula -
[tex]d=\frac{ZM}{N_Aa^3}[/tex]
[tex]a=[\frac{ZM}{N_Ad}]]^\frac{1}{3}[/tex]
Now, putting the given values
[tex]a=\frac{4\times40.13g/mole}{6.022\times10^2^3\times(3.58g/cm^3)}[/tex]
[tex]4.21\times10^-^8 cm[/tex]
= 0.421 nm
Hence , the unit cell edge length = 0.421 nm
The unit cell edge length of magnesium oxide (MgO) is equal to 0.421 nanometer.
Given the following data:
Density = 3.58 [tex]g/cm^3[/tex]Atomic weight of magnesium = 24.31 g/mol.Atomic weight of oxygen = 16.00 g/mol.Scientific data:
Avogadro's number = [tex]6.02 \times 10^{23}[/tex]Z for FCC = 4Molar mass of magnesium oxide (MgO) = [tex]24.31 + 16 = 40.31 \;g/mol.[/tex]To determine the unit cell edge length:
Mathematically, the unit cell edge length for a face-centered cubic (FCC) structure is given by the formula:
[tex]a=\sqrt[3]{\frac{ZM}{\rho N_A} }[/tex]
Where:
Z is the number of atoms per unit cell.[tex]\rho[/tex] is the density.M is the molar mass.[tex]N_A[/tex] is the Avogadro constant.Substituting the given parameters into the formula, we have;
[tex]a=\sqrt[3]{\frac{4 \; \times \;40.31}{3.58\; \times \;6.02 \times 10^{23}} }\\\\a=\sqrt[3]{\frac{161.24}{2.16 \times 10^{24}}}\\\\a=\sqrt[3]{7.47 \times 10^{-23}} \\\\a=4.21 \times 10^{-8}\;meter[/tex]
Note: [tex]1 \;nanometer = 1 \times 10^{-9} \;meter[/tex]
a = 0.421 nanometer.
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Of the following elements aluminum, magnesium, aluminum, silicon, and sodium which has the smallest atomic radius? Explain your answer.
Answer:
Sodium
Explanation:
Radius grows as you go down and to the right on the ptable.
What is the oxidation state of copper in Cu(C2H3O2)2? +2 -1 -2 +4 +1
How many moles of H,O must be decomposed to form 200 moles of H,?
24,0 2H +0,
Answer:
300
Explanation:
at least 300 molecules
IBNEED HELP ASAP
NO BULL I NEED ACTUAL HELP
Answer:
god says dont use any assault language okay?
Explanation:
Jack has a rock. The rock has a mass of 14g and a volume of 2cm3. What is the density of the rock?
Answer:
The density is 7 g/cm^3
Explanation:
The formula for density is p=m/V. Where p is the density, m is mass, and V is the volume. 14/2=7.
the form of energy that your lunch represents is?
A) electrical
B) chemical
C) thermal
D) nuclear
what are the two components of a solution
How is activation energy represented on an energy diagram?
Energy
Reactants
Products
Reaction Progress
O A. Activation energy is the distance from the reactants to the top of
the "hill."
B. Activation energy is the distance from the top of the "hill to the
products.
O C. Activation energy is the final energy level of the product
molecules.
o
D. Activation energy is the starting energy level of the reactant
molecules.
In accordance with the diagram, activation energy is the distance from the reactants to the top of the "hill"
The activation energy represented on the energy diagram is as given as
"Activation energy is the distance from the reactant to the top of the hill"
So, the correct option is A.
What is activation energy?The minimum amount of energy required by the reactant to do the reaction is called activation energy.
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What form of electromagnetic radiation does gamma radiation use?
Answer:
Gamma-rays are a form of electromagnetic radiation, as are radio waves, infrared radiation, ultraviolet radiation, X-rays and microwaves. Gamma-rays can be used to treat cancer, and gamma-ray bursts are studied by astronomers.
Explanation:
Hope this helped Mark BRAINLIEST!!!
Gamma Rays are ionizing Electromagnetic radiation, obtained by the decay of an atomic nucleus. Gamma rays are more penetrating, in matter, and can damage living cells to a great extent. Gamma rays are used in medicine (radiotherapy), industry ( Sterilization and disinfection) and the nuclear industry.
9 moles of Ammonia (NH3) are added to 50 L of H2O at a temperature of 29°C. The vapor pressure of water alone is 29.96 mmHg at 29°C. What is the vapor pressure of the Ammonia solution?
Answer: The vapor pressure of the solution at [tex]29^0C[/tex] is 29.86 mm Hg
Explanation:
As the relative lowering of vapor pressure is directly proportional to the amount of dissolved solute.
The formula for relative lowering of vapor pressure will be,
[tex]\frac{p^o-p_s}{p^o}=i\times x_2[/tex]
where,
[tex]\frac{p^o-p_s}{p^o}[/tex]= relative lowering in vapor pressure
i = Van'T Hoff factor = 1 (for non electrolytes)
[tex]x_2[/tex] = mole fraction of solute
=[tex]\frac{\text {moles of solute}}{\text {total moles}}[/tex]
Given : 9 moles of [tex]NH_3[/tex] are dissolved in 50 L or 50000 ml of water
mass of water = [tex]density\times volume = 1g/ml\times 50000ml=50000g[/tex]
moles of solvent (water) = [tex]\frac{\text{Given mass}}{\text {Molar mass}}=\frac{50000g}{18g/mol}=2778moles[/tex]
Total moles = moles of solute + moles of solvent = 9 mol + 2778 mol = 2787
[tex]x_2[/tex] = mole fraction of solute
=[tex]\frac{9}{2787}=3.2\times 10^{-3}[/tex]
[tex]\frac{29.96-p_s}{29.96}=1\times 3.2\times 10^{-3}[/tex]
[tex]p_s=29.86mmHg[/tex]
Thus the vapor pressure of the solution at [tex]29^0C[/tex] is 29.86 mm Hg
Shaun's doctor has recommended that he consume 200 calories of protein a day. Shaun consumed 176 calories of protein in one day. How much more protein does he need to consume to reach the required amount? (1 gram of protein = 4 calories)
Answer: Shaun must consume 6 more g of protein to reach the required amount.
Explanation:
Given : Recommended amount of protein = 200 calories
Now 4 calories = 1 gram of protein
Thus 200 calories = [tex]\frac{1}{4}\times 200=50[/tex] g of protein.
Calories consumed per day by Shaun = 176 calories
176 calories = [tex]\frac{1}{4}\times 176=44[/tex] g of protein.
Thus Shaun need to consume = (50-44) g = 6 of protein to reach the required amount.
Shaun must consume 6 more g of protein to reach the required amount.
helppppp will mark brainlest
Answer:
if you will decrease the HCO3- so the less H+ ion will be form and reaction will more likely shift to product and when HCO3- decreases pH value increases and vica versa for the increasing HCO3 the more H+ ion will be form and reaction will shift to product and the pH value will decreases!!
I've doubt in reaction shift coz whatever is the amount of HCO3- this is completely gonna form number of H+ so reaction shift may or may not be same!!
answer 1-5 of lesson outline for brainiest
Answer:
see explanation
Explanation:
1. mid-ocean ridge
2.gravity
3.normal,reverse
4.cools
5.stripes
6.spreading
7.continents
The Kinetic Molecular Theory describes the behavior as well as the characteristics of an ideal gas. What are the five postulates of this theory? Provide at least 3 examples to describe these postulates.
Answer:
See explanation
Explanation:
The postulates of the kinetic theory of matter are;
Every substance is made up of tiny particles called molecules. Brownian motion and diffusion illustrates this fact.The molecules that compose matter are in constant random motion.There exists an attractive force between the molecules in matter. The attractive forces between gases are negligible. Solids have a definite shape and volume due to a high magnitude of intermolecular forces. Liquids have a volume but no definite shape due to weaker intermolecular forces. Gases have the weakest intermolecular forces hence the do not have both a shape and volume. They take on the volume of the container into which they are put. This illustrates this fact.The actual volume occupied by gas molecules is negligible relative to the volume of the container. The fact that gases are easily compressible illustrates this fact.Temperature is a measure of the average kinetic energy of the molecules of a body.You have to make 500 mL of a 1.50 M BaCl2. You have 2.0 M barium chloride solution available. Determine how to make the needed dilution
Answer:
You need 375 mL of BaCl2 solution.
Explanation:
M1V1=M2V2
Dilution formula. Substitute known values and solve for V1.
M1 = 2.0 M
M2 = 1.50 M
V2 = 500 mL
(2.0 M)(V1) = (1.50 M)(500 mL)
V1 = (1.50 M)(500 mL) / (2.0 M)
V1 = 375 mL
The use of uranium-238 to determine the age of a geological formation is a beneficial use of
O 1.
nuclear fusion
2.
nuclear fission
3.
radioactive isomers
4.
radioactive isotopes
Answer:
4- radioactive isotopes
Explanation:
I don't remember exactly but this question was on the regents
Uranium-238 is a non- fissile element. It is a radioactive isotope that can be best used to determine geological formations. Thus, option 4 is correct.
What are radioactive isotopes?Radioactive isotopes are elements that have an unstable atomic nucleus and can undergo radioactive decay to produce new particles and energy. They have the same atomic number as that of their parent species.
Isobars are a substance that has atomic mass and do not include uranium. Nuclear fusion and fission are the processes of nuclear energy that combine or splits the unstable nucleus to form a new particle.
Therefore, option 4. Uranium-238 is a radioactive isotope.
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Certain race cars use methanol (CH 3 OH) as fuel. The combustion of 9.8 moles of methanol produces what mass of water?
The combustion of 9.8 moles of methanol will produce 352.8 grams of water.
Stoichiometric calculationFirst, let us look at the balanced equation of combustion of methanol:
[tex]2CH_3OH(l)+3O_2(g)-- > 2CO_2(g)+4H_2O(l)[/tex]
The ratio of number of moles of methanol burned and that of water produced is 1:2.
Thus, 9.8 moles of methanol will produce 19.6 moles of water.
Mass of 19.6 moles water = 19.6 x 18 = 352.8 grams
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Theories must be supported by many lines of evidence.
True
or
False