Answer:
mass number- 7 (round it to 7
Explanation:
PLEASE SOMEONE HELP ME ANSWER THIS!!!! i’m desperate:,,(
Answer:
See detailed solution below
Explanation:
Now, let us solve each question step by step.
1) Given that;
N = amount of radioactive material at time t
No= amount of radioactive material originally present
t = time required for N amount of radioactive material to remain
t1/2= half life of the radioactive material
So,
N/No = (1/2)^t/t1/2
N/60 = (1/2)^22.8/3.8
N/60= (1/2)^6
N/60=1/64
64 N = 60
N = 60/64
N = 0.9 g
2) N/No = (1/2)^t/t1/2
N/8 = (1/2)^103.2/34.4
N/8 = (1/2)^3
N/8 = 1/8
8N = 8
N = 1 L
3) N/No = (1/2)^t/t1/2
50/No = (1/2)^18/6
50/No = (1/2)^3
50/No = 1/8
No = 50 * 8
No = 400 micrograms
4) N/No = (1/2)^t/t1/2
62.5/500 = (1/2)^26/t1/2
0.125 = (1/2)^26/t1/2
Since 0.125 = 1/8
1/8 = (1/2)^26/t1/2
(1/2)^3 = (1/2)^26/t1/2
Hence;
3 = 26/t1/2
t1/2 = 26/3
t1/2 = 8.7 hours
A bus travels 20km in 30 min what is the average speed of the bus
Answer:
40km/h
Explanation:
v=20km/0.5h=40km/h.
Answer:
average speed=distance/time
speed=20/30
speed=2/3
Can someone tell me the answer plz plz I’ll give you brainlist and points plz This is my final test No wrong answers
Answer:
Energy can enter or exit an open system
Explanation:
D
What would happen if a neutron was added to Lithium (7)
Answer:
if you add a neutron to lithium-7 it becomes a compound nucleus of lithium-8
what hypothesis is best for chemical reaction?
will give Brainliest
Answer:
If the reactants in the chemical reactions are known, then the products can be predicted because the pattern of the chemical reactions is being followed. The pattern for a single replacement is A + BC --> AC + B. This is like the Hear It Pop Chemical Reaction which is also an example of the single replacement.
Explanation:
The solubility of ZnCO3 in water is quite low. What could you add to increase the solubility? Explain fully how your method would work.
There is a way to decrease the concentration of an ion here. The carbonate ion happens to be easy to decrease. All we have to do is add some acid (say HCl) to the container. The following sequence of reactions explains how this WO r ks.
As long as more acid is added, this process will continue until all the solid Zn CO3 has been dissolved
Can someone please help me out
Answer:
a. increases
b. increases
c. decreases
What is the name of each labeled part?
Answer:
A - dendrites
B - cell body
C - axon terminal
D - myelin sheath
E - nucleus
Hope that helps.
A-dendrite
B-cell body
C-axon terminal
D-axon
E-nucleus
8. Draw the structural formula for isoprene (the building block of rubber). It should satisfy the molecular formula for isoprene of C5H8.
plz i need help
Here are two options use the one you need :)
If molten sodium chloride is split by electrolysis, which reaction occurs at the anode?
2Cl2 (g) →2Cl− (l) + 2e−
2Cl− (l) →Cl2 (g) + 2e−
2Na (l) →2Na+ (l) + 2e−
2Na+ (l) + 2e−→2Na (l)
Answer: [tex]2Cl^-(l)\rightarrow 2e^-+Cl_2(g)[/tex]
Explanation:
Electrolysis of a subastance is breaking it into its constituents by the action of electrical current.
In the electrolysis of molten sodium chloride, sodium metal is produced at the cathode which is a negative electrode and chlorine gas produces as the anode which is a positive electrode.
[tex]2NaCl(l)\rightarrow 2Na^++2Cl^-[/tex]
At anode : [tex]2Cl^-(l)\rightarrow 2e^-+Cl_2(g)[/tex]
At cathode : [tex]2Na^+(l)+2e^-\rightarrow 2Na(l)[/tex]
2Cl- (l) → Cl2 (g) + 2e-
How many atoms are in HCOOH₂?
Answer:
11 atoms I think
Explanation:
Answer: 3
Explanation:
I took the test!!
Is the chemical reaction between magnesium metal and hydrochloric acid solution an acid base reaction?
Answer:
No
Explanation:
The chemical reaction between magnesium metal and hydrochloric acid solution is not an acid - base reaction.
An acid - base reaction involves an acid and base to produce salt and water.
This reaction is called a neutralization reaction. An acid is a substance that produces excess hydroxonium ions in solutions. A base produces excess hydroxyl ions in solution. When acids and base combines, the main product is a salt in water solution.the transfer of energy by waves is also known as _______
Answer:
wave
Explanation:
'Wave' is a common term for a number of different ways in which energy is transferred: In electromagnetic waves, energy is transferred through vibrations of electric and magnetic fields.
i hope this helps and your welcom
A can of cola contains approximately 240 calories. If you consume two cans of cola each day for one week, approximately how many calories did you consume from cola?
Select one:
a. 3,400 calories
b. 70 calories
c. 1,700 calories
d. 480 calories
Use the graph to determine the instantaneous speed at 2 seconds.
What is the average speed over the entire trip?
Answer:
The instantaneous speed at 2 seconds =
3 m/s
The average speed over the entire trip is
2 m/s
Explanation:
Answer above is wrong and doesn't state anything about the answer, so this is the correct answer hope this helped! :)
Answer:
1.) 3 m/s 2.) 2 m/s
Explanation:
I hope this helps!!
2H2O2
1. Number of hydrogen atoms in chemical formula 1.
Answer:
А There are two peroxide molecules on the reactant side.
The statement is correct because the left hand side is the reactant side. We can read the reaction as;
2 molecules of hydrogen peroxide decomposed to given 1 molecule of oxygen gas and 2 molecules of water .
D Mass must be conserved so there are an equal number of molecules in the reactants and products.
E Mass must be conserved so there are an equal number of atoms in the reactants and products.
Since the chemical equation is balanced, choices D and E are correct. The reaction will have equal number of molecules and atoms on both sides of the expression.
Explanation:
how many grams of solid silver nitrate would you need to prepare 200.0 mL of a 0.150 M AgNO3 solution
which of the following is a renewable resource a. copper b. aluminum c. peanut oil d. natural gas
Answer: c. peanut oil
Explanation:
Which statement correctly describes compounds? (Please Hurry)
Compounds cannot be broken down into simpler substances by chemical means.
Each compound is composed of one type of molecule.
Compounds can be broken down into simpler substances by physical means.
Each compound is composed of one type of atom.
Answer:
a
Explanation:
because
Answer:
A.) Compounds cannot be broken down into simpler substances by chemical means.
Explanation:
just took test on e2020 :)
Choose two different particles found in the air. Explain how they are different and how they are the same
Answer:
Dust and smoke.
Explanation:
Dust and smoke are two different particles present in the air. Dust and smoke are different from one another due to their origin. Smoke formed from burning of materials while dust refers to the soil particles lifted by the wind due to their light weight. Dust and smoke are similar to each other due to their small in size, infinite number means uncountable and light weight.
Air is a mixture of gases and consists of dust particles and water vapor. It consists of small to very large size of particles. Some of them include dust pollen, soot, and liquid droplets.
Dust and soot particles of the air are different as the soot is a fine black particle of carbon and tar. It is made by the incomplete combustion of air. While dust is fine dry particles of matter.Hence they both differ.
Learn more about the two different particles found in the air.
brainly.in/question/35683807.
The table shows data for two groups of plants one grown with fertilizer and the other without fetalizer was the mean height of the plant given fertilizer
Answer:
What is the question?
Explanation:
How do we get heat from the sun?
Answer:
When the Sun's energy moves through space, it reaches Earth's atmosphere and finally the surface. This radiant solar energy warms the atmosphere and becomes heat energy. This heat energy is transferred throughout the planet's systems in three ways: by radiation, conduction, and convection.
Explanation:
Answer:
The sun radiates energy in all directions. Most of it dissipates into space, but the tiny fraction of the sun's energy that reaches Earth is enough to heat the planet and drive the global weather system by warming the atmosphere and oceans. The delicate balance between the amount of heat Earth receives from the sun and the heat that Earth radiates back into space makes it possible for the planet to sustain life.
Hopefully, this helps you out!
It requires energy to melt ice. Applying salt to the ice created a chemical reaction melting the ice. Were did the energy come from to melt the ice? *
Answer:
HOPE IT HELPS...
Explanation:
When added to ice, salt first dissolves in the film of liquid water that is always present on the surface, thereby lowering its freezing point below the ices temperature. Ice in contact with salty water therefore melts, creating more liquid water, which dissolves more salt, thereby causing more ice to melt, and so on
Once a ball is hit and no longer touches the mallet, it continues moving.
What causes the ball to continue moving?
Part of an important cellular process involving a DNA strand is modeled below
12000
What is the purpose of this cellular process?
F Preserving genetic information for future generations
G Deleting the information in the sequence produced from the DNA template
# Transcribing information in the DNA sequence for use by the cell
J Producing more nucleotides for the DNA sequence
Answer: transcribing information to the dna sequence for use by the cell
Explanation:
A positive ion is —————-than its parent atom?
Answer:
positive ions are smaller than their parent atoms and negative ions are larger than their parent atoms.
does SiF4 have polar covalent bonds?
Answer:
SiF4 is not a polar covalent bond.
Explanation:
SiF4 is a nonpolar molecule because the fluorine's are arranged around the central silicon atom in a tetrahedral molecule with all of the regions of negative charge cancelling each other out.
What math is used to find density?
Answer:
[tex]\huge\mathtt{{\colorbox{silver}{ANSWER~~~↴}}}[/tex]
Density is the mass of an object divided by its volume. Density often has units of grams per cubic centimeter (g/cm3). Remember, grams is a mass and cubic centimeters is a volume (the same volume as 1 milliliter).
▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃▃
Which learning theory is based on associative learning?
Answer:
1. Classical conditioning. Classical conditioning is a type of associative learning based on the association between a neutral stimulus with another that is significant for a person or an animal in order to generate a similar response.
Have a great day/night, and stay safe!
The murder weapon weighs 150 grams. The initial temperature of the weapon before being tested was 100 oC. After placing the weapon in the water, the temperature dropped to 25.13 oC. Find the specific heat capacity of the unknown metal by first calculating the heat energy gained by the water.
Water
Mass = 2500 g
Initial temperature = 25 o C Final temperature = 25.13 oC
Equations
q = m C p Δ T C p = q / (mΔT)
1. How much heat energy (q) did the water gain?
2. What is the specific heat capacity (C p) of the unknown metal?
3. Compare the heat capacity you calculated with the one below, which one matches?
Specific heat capacity of metal (J / g or C)
Silver 0.235
Gold 0.129 Lead 0.121
Copper
4. What metal was the murder weapon made of?
0.385
1. heat gained : 1358.5 J
2. Cp metal = 0.121 J/g C
3/4 The metal = Lead
Further explanationThe law of conservation of energy can be applied to heat changes, i.e. the heat received/absorbed is the same as the heat released
Q in = Q out
Heat can be calculated using the formula:
Q = mc∆T
Q water(gained) = Q metal (lost)
1. Heat of water gained
[tex]\tt Q=2500\times 4.18\times (25.13-25)=1358.5~J[/tex]
2. The specific heat capacity (C p) of the unknown metal :
[tex]\tt Cp=\dfrac{1358.5}{150\times (100-25.13)}=0.121~J/g^oC[/tex]