Answer:
Each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element. Hope this helps, have a good day! :)
Answer:
atoms with the same number of protons and electrons but different numbers of neutrons
Explanation:
All radioactive sources have a half-life.
Which statement about the half-life of a source is correct?
A. It is half the time it takes for an atom to decay
B. It is half the time for the radioactive source to become safe
C. It is the time it takes the actity of the source to decrease by half
D. It is half the time it takes the activity of the source to decrease to zero
Answer:
The answer is C
Explanation:
Duh its the name HALF LIFE!!
just a way to remember
The statement which is true about the half-life of a source is (D) It is half the time it takes the activity of the source to decrease to zero. Hence the correct option is (D)
What is Half Life Period of a source ?Half-life is the length of time it takes for a radioactive element to decay to half of its initial value.
This suggests that a source's activity has a half-life when it takes time for it to decrease to half its initial value.
It is the amount of time needed for half of the atomic nuclei in a radioactive sample to spontaneously decay, which releases energy and particles into other nuclear species. Alternatively, it is the amount of time needed for the radioactive sample to disintegrate at a rate of one per second.
Therefore, The statement which is true about the half-life of a source is (D) It is half the time it takes the activity of the source to decrease to zero. Hence the correct option is (D)
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How many joules would be released when 256 grams of zinc at 96 c were cooled to 28 c
Answer:
–6562.816 J
Explanation:
From the question given above, the following data were obtained:
Msss (M) = 256 g
Initial temperature (T₁) = 96 °C
Final temperature (T₂) = 28 °C
Heat (Q) released =?
Next, we shall determine the change in temperature. This can be obtained as follow:
Initial temperature (T₁) = 96 °C
Final temperature (T₂) = 28 °C
Change in temperature (ΔT) =?
ΔT = T₂ – T₁
ΔT = 28 – 96
ΔT = –68 °C
Finally, we shall determine the heat released. This can be obtained as follow:
Msss (M) = 256 g
Change in temperature (ΔT) = –68 °C
Specific heat capacity (C) of Zn = 0.377 J/gºC
Heat (Q) released =?
Q = MCΔT
Q = 256 × 0.377 × –68
Q = –6562.816 J
Thus, –6562.816 J of heat energy is released.
Why atoms form compounds
Answer:
Because the atoms are trying to reach the most stable ( lowest energy ) state they can.
Please help me fill in the blanks
Answer: ew i hate science but ive done that same thing before i dont remember the answers though
Explanation:
Balance the following Equation (do not leave any empty blanks, you must enter 1 if the value is 1):
___ Na2S + ___ HCl --> ___ NaCl + ___ H2S
(Refer to image)
What type of reaction is it?
(Question one is a _______ type of reaction.)
Answer: this looks hard
Explanation:
Answer:
1 Na2S + 2 HCl ===> 2 NaCl + 1 H2S
In these reactions, two compounds exchange ions to form two new compounds.
Explanation:
--- Na2S + ---- HCl ===> ---- NaCl + ---- H2S
Na = 2 Na = 1 * 2 = 2
S = 1 S = 1
H = 1 * 2 = 2 H = 2
Cl = 1 * 2 = 2 Cl = 1 * 2 = Cl
In these reactions, two compounds exchange ions to form two new compounds.
REACTION TYPE:
DOUBLE DISPLACEMENT REACTION/DOUBLE REPLACEMENT
I hope that helps, have a wonderful day!!!!
I need help please in this:(
Answer:
That would be A sir or Miss
Explanation: Tell me if I am wrong, Also hope this helped you!
How to solve this problem in Chemistry? I am stuck
The buffer can be made using an acid or a base.
What is a buffer?We have to know that the term buffer is the generic term that can be generally used to describe any solution that is resistant to changes in acidity and the alkalinity of the solution.
We know that we can be able to make a buffer in two ways;
1) By the use of a weak acid and its salt
2) By the use of weak base and its salt.
In each case, the pH of the solution that has been formed would not be easily changed and this is the job of the buffer.
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How many grams of sodium carbonate are produced when 5.3 moles of sodium phosphate reacts with aluminum carbonate?
Answer: There is 842.54 grams of sodium carbonate are produced when 5.3 moles of sodium phosphate reacts with aluminum carbonate.
Explanation:
Chemical equation depicting reaction between sodium phosphate and aluminum carbonate is as follows.
[tex]Al_{2}(CO_{3})_{3} + 2Na_{3}PO_{4} \rightarrow 2AlPO_{4} + 3Na_{2}CO_{3}[/tex]
As this equation contains same number of atoms on both reactant and product side. So, this equation is a balanced equation.
According to the equation, 2 moles of sodium phosphate is giving 3 moles of sodium carbonate.
Therefore, sodium carbonate formed by 5.3 moles of sodium phosphate is as follows.
[tex]\frac{3}{2} \times 5.3 mol\\= 7.95 mol[/tex]
As number of moles is the mass of substance divided by its molar mass. So, mass of sodium carbonate ( molar mass = 105.98 g/mol) is as follows.
[tex]No. of moles = \frac{mass}{molar mass}\\7.95 mol = \frac{mass}{105.98 g/mol}\\mass = 842.54 g[/tex]
Thus, we can conclude that there is 842.54 grams of sodium carbonate are produced when 5.3 moles of sodium phosphate reacts with aluminum carbonate.
A sample of 4.0 L of nitrogen, at 1.2 atmospheres, is transferred to a 12 L container.
What will the pressure be in the new container?
Answer:
The pressure will be 0.4 atm.
Explanation:
The gas laws are a set of chemical and physical laws that allow determining the behavior of gases in a closed system. The parameters evaluated in these laws are pressure, volume, temperature and moles.
As the volume increases, the gas particles (atoms or molecules) take longer to reach the walls of the container and therefore collide with them less times per unit of time. This means that the pressure will be lower because it represents the frequency of collisions of the gas against the walls. In this way pressure and volume are related, determining Boyle's law which says:
"The volume occupied by a certain gaseous mass at constant temperature is inversely proportional to pressure"
Boyle's law is expressed mathematically as:
P*V= k
If you initially have the gas at a volume V1 and press P1, when the conditions change to a volume V2 and pressure P2, the following is satisfied:
P1*V1= P2*V2
In this case:
P1= 1.2 atmV1= 4 LP2= ?V2= 12 LReplacing:
1.2 atm* 4 L= P2* 12 L
Solving:
[tex]P2=\frac{1.2 atm*4 L}{12 L}[/tex]
P2= 0.4 atm
The pressure will be 0.4 atm.
PLEASE HELP 15 POINTS!! Which equation is needed to solve this problem?
Answer:
Option 1
Explanation:
The question is asking us what formula is used to obtain the quantity of heat added to a given mass of mercury in order to cause its temperature to change.
This quantity of heat is obtained from;
q = mcspΔT
Where;
q = quantity of heat added
m = mass of the mercury
csp= specific heat capacity of mercury
ΔT = temperature change
We learned that Energy can
exist in many forms.
Do you think energy can
converted from one form to
another?
What is the molecular weight of MgCl2
The molecular weight of MgCl₂ is 94 g/mol.
What is molecular weight?This refers to the total mass of a compound. It is equivalent to the sum of the individual atomic masses of each atom in the molecule.
Steps to determine the molecular formula of the molecule.
Determine the atomic mass of each element in the molecule.Multiply each element's atomic mass by the number of atoms of that element in the molecule. This number is represented by the subscript next to the element symbol in the molecular formula.Add these values together for each different atom in the molecule.The total will be the molecular mass of the compound.Atomic number of Cl =17
Atomic number of Mg = 12
Mass number of Cl = 35
Mass number of Mg = 24
Calculating the molecular weight of MgCl₂
MgCl₂
=(12* 2) + (35*2)
= 24 + 70
= 94 g/mol.
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Why does the standard model of the universe need to be change?
Explanation:
The standard model of particle physics is a relativistic theory of quantum fields developed between 1970 and 1973 [citation needed] based on the ideas of unification and symmetries [1] that describes the fundamental structure of matter and vacuum considering the elementary particles as irreducible entities whose kinematics is governed by the four known fundamental interactions (except for gravity, whose main theory, general relativity, does not fit the mathematical models of the quantum world). The word "model" in the name comes from the 1970s when there was not enough experimental evidence to confirm the model. [1] To date, almost all experimental tests of the three forces described by the standard model are in agreement. with their predictions. However, the standard model falls short of being a complete theory of fundamental interactions due to several unresolved issues.
A sample of N2 has a volume of 616 mL at 68 °C. What will be its volume at -17 °C?
Answer:
462.5ml
Explanation:
Using Charle's law equation;
V1/T1 = V2/T2
Where;
V1 = initial volume (ml)
V2 = final volume (ml)
T1 = initial temperature (K)
T2 = final temperature (K)
Based on the information provided in this question;
V1 = 616ml = 616/1000 = 0.616L
V2 = ?
T1 = 68°C = 68 + 273 = 341K
T2 = 17 °C = -17 + 273 = 256K
V1/T1 = V2/T2
0.616/341 = V2/256
Cross multiply
341 × V2 = 256 × 0.616
341V2 = 157.69
V2 = 157.69/341
V2 = 0.4625 L or 462.5ml
The table shows the chemical formulas for four substances. Substance Chemical Formula 1 C2H60 CH 2. "8" 18 ليبيا CH,CH_Br C.H.. 4. Which substances have the same number of carbon atoms? A Substances 1 and 2 B Substances 2, 3, and 4 C Substances 2 and 3 only D Substances 1 and 3
In today's experiment, Solutions A and B are prepared as follows.
Solution A: Solution B:
2.0 mL of 3.00 x 10-4 M bromcresol green 2.0 mL of 3.00 x 10-4 M bromcresol green
5.0 mL of 1.60 M acetic acid (HAc) 2.0 mL of 0.160 M sodium acetate (NaAc)
2.0 mL of 0.200 M KCl diluted to a total volume of 50 mL
diluted to a total volume of 50 mL
What is the molarity of HAc in Solution A?
A. 6.4x 10-3
B. 3.20 x 10-4
C. 8.0 x 10-3
D. 0.160
E. 1.60
Answer:
D. 0.160
Explanation:
The solution A is obtained adding 2.0mL of a solution of bromocresol green, 5.0mL of 1.60M HAc and 2.0mL of a solution of KCl. The solution is diluted to 50mL
That means the HAc is diluted from 5.0mL to 50.0mL, that is:
50.0mL / 5.0mL = 10 times.
And the final concentration of HAc must be:
1.60M / 10 times =
0.160M
Right answer is:
D. 0.160CaCO3 (s) + 176 KJ à CaO (s) + CO (g)
A. 176 KJ are released in an endothermic reaction.
B. 176 KJ are released in an exothermic reaction
C. 176 KJ are absorbed in an exothermic reaction.
D. 176 KJ are absorbed in an endothermic reaction.
Answer:
its d
Explanation:
Each of the following sets of quantum numbers is supposed to specify an orbital Choose the one set of quantum numbers that does NOT contain an error.
a) n=4, I=4, m/=1
b) n=5, I=3, m/=- 3
c) n=3, I=1, m/= -2
d) n=3, I= 2, m/=+3
Answer:
C
Explanation:
The correct answer is C because the first quantum numbers containing and encompass in an orbital m contain a definite she'll of 2 and hence
The form of energy carried by moving electrical charges is ____________________ energy.
Answer:
kinetic
Explanation:
hope this helps
Answer:
Kinetic energy
Explanation:
what is the energy of a photon of yellow light with a frequency of 5.2 x 10¹⁴ Hz?
Answer:
3.4x10⁻¹⁹J is the energy of the photon
Explanation:
To find the energy of a photon from its frequency we must use the equation:
E = hf
Where E is the energy of the photon in J, our incognite
h is Planck's constant = 6.6262x10⁻³⁴Js
And f is the frequency = 5.2x10¹⁴Hz = 5.2x10¹⁴s⁻¹
Replacing:
E = 6.6262x10⁻³⁴Js*5.2x10¹⁴s⁻¹
E = 3.4x10⁻¹⁹J is the energy of the photon
How many molecules of H2O are equivalent to 98.2 g of H2O
Answer:
Demo Mole Quantities
58.5g NaCl(mol/58.5g)(6.02 x 1023/mol) = 6.02 x 1023 Na
+
Cl21 pre-1982 pennies (after 1982 pennies are mostly zinc with copper coating)
63.5g Cu( mol/ 63.5g)(6.02 x 1023/mol) = 6.02 x 1023 Cu
19.0g Al (mol/27.0g)(6.02 x 1023/mol) = 4.24 x 1023 Al
Explanation:
The density of oxygen gas at a certain temperature and pressure is 1.345 g cm-3. How many oxygen atoms are present in 2.0 L of oxygen gas at this same temperature and pressure?
The number of oxygen atoms present in 2.0L of oxygen gas at same temperature and pressure is 5.1 × 10²² atoms.
How to calculate number of atoms?The number of atoms of a substance can be calculated by multiplying the number of moles in the substance by Avogadro's number (6.02 × 10²³).
no of atoms = no of moles × 6.02 × 10²³
According to this question, the density of oxygen gas at a certain temperature and pressure is 1.345 g cm-³. If 2.0 L of oxygen gas is given, the mass of the oxygen gas can be calculated as follows:
mass = 1.345 × 2 = 2.69grams
moles = 2.69g ÷ 32g/mol = 0.084moles
No of atoms = 0.084 mol × 6.02 × 10²³
no of atoms = 5.1 × 10²² atoms
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Anyone know this
Please help me
Answer:
sorry I don't know
Explanation:
have a great time with your family and friends
Please show all of your work, I need to understand all steps:
A student collected time (t) and concentration ([A]) data at
295 K for the reaction 2A→B. These time and concentration data are shown in the table to the right. The student then plotted graphs of [A] versus t (Figure 1) , ln[A] versus t (Figure 2) , and 1/[A] versus t (Figure 3) .
Figure 1:
t (s) (A)(M) ln(A) 1/ (A)
0.00 0.500 −0.693 2.00
20.0 0.389 −0.944 2.57
40.0 0.303 −1.19 3.30
60.0 0.236 −1.44 4.24
80.0 0.184 −1.69 5.43
i.) What is the rate of the reaction?
ii.) What is the value of the rate constant for this reaction?
iii.)
Next, the student ran the same reaction at a different temperature and measured a different reaction rate, with the following results:
T(K) k(s-1)
295 0.0125
325 0.0357
What is the activation energy of this reaction?
Express your answer to three significant figures and include the appropriate units.
Answer:
a because the x and y value is the same
The Sun is located _____.
in the central core of the Milky Way galaxy
in the bar of the Milky Way
in an arm about 25% of the distance from the center of the Milky Way to its outer edge
in an arm about 75% of the distance from the center of the Milky Way to its outer edge
Answer:
I believe the answer is going to be A. in the central core of the Milky Way galaxy.
Explanation: lol sorry I put it in the question box instead of answering it, hope this helps!
How many moles of magnesium atoms react with 1 mole of oxygen molecules?
1 mole of magnesium atoms will react with 2 moles of oxygen molecules. This is because the chemical equation for the reaction between magnesium and oxygen is: Mg + O2 → MgO.
What is chemical equation?A chemical equation is a symbolic representation of a chemical reaction, showing the reactants (starting materials) on the left side and the products (resulting substances) on the right side. The symbols used to represent the reactants and products are chemical formulas, which use the symbols of the elements in the reaction. The arrow between the reactants and products indicates the type of reaction taking place. The coefficients next to the symbols and formulae of entities indicate the number of moles of each species that are involved in the reaction. The overall reaction is balanced when the number of atoms of each element on the left side of the equation is equal to the number of atoms of that element on the right side of the equation.
This equation shows that for every 1 mole of magnesium atoms, 2 moles of oxygen molecules are required for the reaction to take place. Therefore, 1 mole of magnesium atoms will react with 2 moles of oxygen molecules.
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Because the mass of the flask with water exceeds the amount that can be weighed on the digital balances, the triple-beam-balance is used, which only weighs to the nearest 0.01 g. Why doesn't using this balance affect the number of significant digits to which the experimental molecular weight of carbon dioxide can be reported
Answer:
The Less accuracy of this method is the reason for this balance affecting the number of significant digits to which the experimental molecular weight of carbon dioxide can be reported.
Explanation:
As we know the triple-beam-balance method is a less accurate method of measurement of mass.
An accurate molecular weight is not required in this case. So, this method is being used because much accuracy is not required.
That is why this balance affects the number of significant digits to which the experimental molecular weight of carbon dioxide can be reported.
4. A student poured 50 cm^3
water into a beaker and
measured the water's
temperature. The student added
1.00 g calcium chloride to the
water, stirred the mixture and
then recorded the temperature.
The concentration of a calcium
chloride solution is 12 g/dm^3.
Calculate the volume of this
solution, in cm^3, that contains
9.0 g of calcium chloride.
Answer:
V = 750 cm³
Explanation:
The volume of the solution can be calculated by the following formula:
[tex]V = \frac{M}{C}[/tex]
where,
V = Volume of solution = ?
M = Mass of Calcium Chloride = 9 g
C = Concentration of Solution = 12 g/dm³
Therefore,
[tex]V = \frac{9\ g}{12\ g/dm^3}\\\\V = (0.75 dm^3)(\frac{1000\ cm^3}{1\ dm^3})[/tex]
V = 750 cm³
10 points
Scenario: Calculate the new temperature when a 2.0 L of a gas at 220 K is compressed to 1.0 L.
Hint! You should check three boxes: one to describe particle speed, one to describe particle spacing and one to describe number of particle collisions.
Question 5 options:
The particles speed up.
The particles slow down.
The particle speed doesn't change.
The particles get squished (compressed) together.
The particles float farther apart.
The distance between particles doesn't change.
The amount of collisions among particles in the gas sample increase.
The amount of collisions among particles in the gas sample decrease.
The amount of collisions among particles in the gas sample doesn't change.
Answer:
The 2nd, 4th, and 7th options
Explanation:
WILL MARK BRAINLIEST!!
Which situation indicates a beta emission?
The atomic number increases by one, but the mass number does not change.
The atomic number decreases by two, and the mass number decreases by four.
The atomic number decreases by one, and the mass number decreases by one.
The atomic number and the mass number both decrease by two.
Answer:
A: The atomic number increases by one, but the mass number does not change.