Answer:
s=d/t. d=540 t=9h
540÷90=6 km/h
Zn-71 has a half life of 2.4 minutes. If one had 100g at the beginning, how many grams would be left after 12 minutes?
3.125g
Explanation
2.4 minutes = 1 half life
so 12 minutes = 5 half lives (12/2.4)
100g/2 = 50g (1 half life)
50g/2 = 25g (2 half lives)
25g/2 = 12.5g (3 half lives)
12.5g/2 = 6.25g (4 half lives)
6.25g/2 = 3.125g (5 half lives)
PLEASE…. Select the number line that shows that two opposite numbers have a sum of
0.
3
A.
4321 01 2 3 4 5 6 7 8 9 10 11 12
B.
4 3 2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12
6
С.
-432-10 3 5 6 7 8 9 10 11 12
2
Answer:
C A
Explanation:
The the number line that shows that two opposite numbers have a sum of 0 is 4 3 2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12. The correct option is B.
What is number line?A number line is a picture of a graduated straight line that serves as a visual representation of real numbers in elementary mathematics.
Every point on a number line is assumed to be a real number, and every real number is assumed to be a point.
4 3 2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12
We can see from this number line that the inverse of each number is located at an equal distance from 0.
For example, the inverse of 3 is -3, which is the same distance from 0 as 3. Similarly, the inverse of -1 is 1, which is the same distance from 0 as -1.
Thus, the correct option is B.
For more details regarding number line, visit:
https://brainly.com/question/16191404
#SPJ5
Which statement describes why sodium reacts more vigorously than magnesium to hydrochloric acid? Refer to the periodic table. Circle the letter of the correct answer.
1) Sodium has a smaller atomic radius than magnesium.
2)Sodium has a lower ionization energy than magnesium.
3)Magnesium has a lower ionization energy than sodium.
Answer:
Its B all the others arent true and also dont make any sense
Explanation:
Sodium has a lower ionization energy than magnesium describes why sodium reacts vigorously than magnesium chloride.
Why is sodium more reactive than magnesium?Sodium is more reactive than magnesium because it has the ability to easily lose electron, hence have lower ionization energy.Sodium belong to group one on the periodic table and they are called akali metal while magnesium belong to group two on the periodic table and they are called alkali Earth metal.Sodium and magnesium belong to the in the 3rd period. Iin the outermost energy level sodium has one electron but magnesium has 2 electrons. Therefore, there is more attraction abetween the nucleus and electrons in magnesium than that of sodium.Therefore, sodium is more reactive than magnesium chloride because of lower ionization energy.
For more details on sodium reactivity, check the link below.
https://brainly.com/question/6837593
What foods have been allowed or banned in which countries? Why?
please please help me
What is the molarity of a 75.0 mL solution that contains 0.225 g of
potassium nitrate?
Answer:
M=0.0297M
Explanation:
we know that molarity equals number of mole of solute over the volume of solution.
M=n/V but n=m/M
n=0.225g÷101g/mol =0.00223mol
M=0.00223mol/0.075l
M=0.0297M
Answer:
0.0297M
Explanation:
We will use the formula M= moles of solute/lites of solution.
First we need to figure out the Moles of the solute, to get this we first need the molar mass of KNO3 (potassimum nitrate).
The Molar Mass of potassimum nitrate is 101.103 g/mol
K - 1 x 39.09
N - 1 x 14.006
O - 3 x 15.999
KNO3 - 101.103 g/mol
Now we get the moles of the solute by doing.
0225g/ 101.103g/mol = 0.00223 mol
Put the answer into the orginal equation to get 0.00223mol / 0.045 L
Which equals to 0.0297M. This is also the correct amount of significant figures.
The bacteria are known to be prokaryotes. Prokaryote means
A
organisms whose cells have no nucleus
B
organisms who are made of many cells
C
organisms who make their own food
D
organisms whose cells have a nucleus
Answer:
prokaryote, also spelled procaryote, any organism that lacks a distinct nucleus and other organelles due to the absence of internal membranes. ... Bacteria are among the best-known prokaryotic organisms. The lack of internal membranes in prokaryotes distinguishes them from eukaryotes.
Explanation:
Why is eating animals to obtain energy considered exothermic
Which of the following is the strongest covalent bond?
Single bond
Double bond
Triple bond
Hydrogen bond
Answer:
Triple bond is the strongest bond
Triple bonds are stronger than the equivalent single bonds or double bonds, with a bond order of three.
Answer:
single bond.In a single covalent bond, when the electrons are shared between two s orbitals, the resulting bond is a sigma (σ) bond . Sigma bonds are the strongest covalent chemical bonds....!!
Which of the following is the correct chemical symbol for Aluminium?
A: AL
B: Al
C: aL
D: al
3. Type: MT
Match the term to the correct definition
1. Homogeneous mixture
a. same throughout
2. Heterogeneous mixture
b. different throughout
Homogeneous mixture - same throughout
Heterogeneous mixture - different throughout
Answer: Homogeneous Mixture : B(different throughout)
Heterogeneous Mixture : A(same throughout)
using the two ways you have learned about between temperature, pressure and volume, what are two ways you could increase the gas pressure of a system.
Answer:
I don't know do you know tell me please
please help me on this question plizzźzz
what is the green colouring matter found in plants called
Answer:
the answer is chlorophyll....
Explanation:
if u need it's purpose just let me know
Explanation:
the green colouring matter found in plants is called chlorophyll.
• If the distance between Earth and the Moon decreased by half, how would it affect the
weight of a person on Earth?
Answer:
look at the explanation
Explanation:
Tides would be much higher also A lunar month would be about 10 days rather than 29 days, so the phases of the moon would go much quicker.
What is photosynthesis?
Explanation:
the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a byproduct.
Answer:
photosynthesis is the process of making food by green plants by using sunlight,carbon dioxide, water.
Mr. Green gave his students a set of items.
They had a toothpick, pencil, paper clip, safety pin, nail, and dime. He also gave them a magnet. He told them to predict which items are magnetic.
How can they test their predictions?
A.
weigh each of the items
B.
see which items stick to the pencil
C.
measure each of the items
D.
see which items stick to the magnet
Answer:
D. see which items stick to the magnet
Explanation:
To predict which items are magnetic, the students will have to test whether or not each item is attracted to the magnet. Only objects that are magnetic stick to a magnet, so all of the items that stick to the magnet should be magnetic.
Hopefully that's helpful! :)
during hybridization ______.
A) nature selects which organisms will survive and reproduce.
B) the nucleus of a cell is removed.
C) two organisms with desired traits are bred.
D) a single beneficial trait is bred into a species.
Answer:
option C two organisms with desired traits are bred
when an atom in an excited state returns to its ground state it
Answer:
Inside the Atom
Just like bricks are the building blocks of a home, atoms are the building blocks of matter. Matter is anything that has mass and takes up space (volume). All matter is made up of atoms. The atom has a nucleus, which contains particles of positive charge (protons) and particles of neutral charge (neutrons). Surrounding the nucleus of an atom are shells of electrons - small negatively charged particles. These shells are actually different energy levels and within the energy levels, the electrons orbit the nucleus of the atom.
Elements that are usually shiny and good conductors of heat and electricity are known as_______.
Points: 70
What is the volume in mL of 1 Kg of gold? The density of gold is 19.3 g/mL.
Answer:
Volume occupied is approx.
38 ⋅ ML
Explanation:
Density ρ = Mass Volume And thus Volume = Mass ρ = 1.592 ⋅ l b × 454 ⋅ g ⋅ l b − 1 19.3 ⋅ g ⋅ m L − 1 = ? ? ⋅ m L
Select the correct answer.
Tropical forests contain dense trees, which allow less sunlight to penetrate. Emergent trees are trees that grow to a height of more than 45 to 55 meters, above the usual height of trees in tropical forests. Which system provides the best possible explanation for why these trees grow to those heights?
A.
shunted growth pattern
B.
homeostasis
C.
due to less exposure to sunlight
D.
phototropism
Please help me with this three questions
Answer:
1. A. Thyroid Gland Function
B. detecting Blood Clots
C. Treating Cancer
2. An example would be how many are used as tracers for diagnostic purposes
3. Beneficial because it gives us ways to eleminate pests, by the sterile insect technique
Number three is kinda iffy a bit difficult to explain it may be explained better in your book.
A substance that takes the shape and volume of its container is in this phase is called a liquid
Answer:
liquid matter
Explanation:
Which animal is found in the desert?
monkeys
parrots
buffalo
meerkats
Answer:
meerkats
Explanation:
Is it unbalanced or balanced if hydrogen reacts to iodine?
Answer:
unbalanced
Explanation:
because it is REACTing.
The pH scale is used to tell if a substance
is an acid or base. Substances with a pH
of 7 are neutral. An acid is anything
below 7 and a base is anything above
7.What would a household cleaner with a
pH of 10 be considered on the pH scale?
Answer:
Explanation:
pH > 7 as 10 is more than 7
The cleaner is very corrosive.
It is a moderately basic. If it was 12 that would make it much more basic (100 times more basic).
I WILL GIVE BRAINLIEST TO THE RIGHT ANSWER
Which of the following substances would have the strongest
intermolecular forces of attraction present? *
A) HF (Hydrogen Fluoride)
B) HCI (Hydrogen Chloride)
C) HBr (Hydrogen Bromide)
D) HI (Hidrogen lodide)
Answer:
A) HF (Hydrofluoric acid)
Explanation:
dw I gotchu. So first off there are three types of intermolecular forces of attraction: 1) London-Dispersion, 2) Dipole-Dipole, 3) Hydrogen-Bonding Attraction Forces. That is also ranked in increasing strength, with Hydrogen-Bonding Attraction Forces being the strongest. Every molecule has London-Dispersion forces present and all the diatomic molecules listed have dipole moments of a certain debye (or Coloumb-meter) value. Both are irrelevant here so dw about that. Lets look at the strongest attraction: the hydrogen-bonding one. Now, don't get confused bc all of these acids are bonded to H bc hydrogen-bonding attraction forces only occur when H is bonded to N, O, or F. So Process of Elimination, hydrofluoric acid (HF) has the strongest intermolecular forces of attraction.
Note: If you don't know what inter/intra molecular forces of attraction are, ill give u a quick summary. Intermolecular refers to electrostatic attractions between molecules while intramolecular refers to the actual bonds, single, double, or triple, binding the atoms together. Well there you have it, have a great day. :)
Which of the following could be classified as producing a physical change?
A. Burning a candle
B. Leaving a bicycle outside to rust
C. Bending sheet metal
D. Toasting a slice of bread
Answer:
C. Bending sheet metal.
Explanation:
The metal is still intact. No change in chemical bonds have occurred.
Burning a candle is converting wax into heat, CO2 and carbon soot.
A rusting bicycle is converting goof iron, Fe, into iron oxide (rust, Fe2O3)
Toasting bread is more difficult to define. If the bread is just warmed, then it is physical. If it is toasted (browned/burned), then a few surface molecules have been converted into tasty carcinogens, my favorite poison.
A chemist dilutes a 1. 0 mL sample of 2. 0 M KNO3 by adding water to it. If the concentration of the solution that is obtained is 0. 0080 M, what is its volume? Use M subscript i V subscript i equals M subscript f V subscript f. 125 mL 250 mL 500 mL 2,000 mL.
Answer:
We know the initial volume of the potassium nitrate solution is 1.0 mL and the initial concentration is 2.0 M, we also know that an unknown volume of water was added to the solution, which diluted our concentration down to a final value of 0.008 M. We are trying to find the final volume.
Here we can use this formula since the initial and final solutions are proportional. Before that let's define our variables.
[tex]M_1 = 2.0 M\\V_1 = \frac{1.0 mL}{1000} = 0.001 L\\M_2 = 0.008 M\\V_2 = \ ?[/tex]
[tex]M_{1}V_{1} =M_2 V_2\\[/tex]
[tex](2.0)(0.001) = (0.008)V_2\\\\\frac{(2.0)(0.001)}{0.008} = V_2\\\\V_2 = 0.25 L \ or \ (0.25 \ * \ 1000) = 250 \ mL[/tex]
Therefore you would have 0.25 L or 250 mL of your final solution.
When you take a hot shower, the
a
shower curtain sometimes moves
into the shower towards you. Why
does this happen?
With hot water comes hot steam, it fills the shower area with steam which raises the air temperature and the air then rises out of the shower
What products are obtained by the electrolysis of CuSO4 solution using copper electrode ? Show with help of chemical reaction.
Answer: The products will be copper and oxygen.
Explanation: Copper electorde is an active electrode so it constantly takes part in the electrolysis. Cathode is a pure copper negative electrode and anode is a impure copper positive electrode. So the copper present in the solution, along with the copper present in the anode will come off and go to the cathode. As a result, cathode gains copper. And the remaining impurities settle down in the bottom.
In the anode, oxygen will be given off because according to the order of discharge, if SO4 is present then the ions will stay in the solution and oxygen will be released. So at the end, solution of SO4 and H2O will be remaining while copper and oxygen is extracted.
The half equations are-
Cathode: Cu2+ + 2e- = Cu
Anode: Cu + 2e- = Cu2+
Something you might not know: The solution in electrolysis turns blue when copper goes to the cathode. So copper electrodes are also used in electroplating.
