Help plzzzzz ASAP!!!!!!!
Answer:
3. The total number of protons and neutrons in an atom is its mass number.
4. The mass number of a helium atom with 2 protons and 2 neutrons is 4.
5. A beryllium atom with 4 protons and a mass number of 9 has 5 neutrons.
6. The chemical symbol is Ne. The atomic number is 10. The mass number is 22.
7. Neon-22
8. Not enough information
Which of the following is an example of quantitative data?
A.five eggs in each nest
B.oval-shaped eggs
C.small eggs
D.blue eggs with white specks
Radon-222 is an alpha emitter with a half life of 3.82 days.
1. What is the mass number of the daughter isotope?
2. What is the element symbol of the daughter isotope?
3. What is the atomic number of the daughter isotope?
The daughter isotope (a decay product): Polonium (Po)
Further explanationRadioactivity is the process of unstable isotopes to stable isotopes by decay, by emitting certain particles,
alpha α particles ₂He⁴ beta β ₋₁e⁰ particles gamma particles γ positron particles ₁e⁰
Radon-222 emits alpha α particles ₂He⁴ , so the atomic number decreases by 2, mass number decreases by 4
Reaction
[tex]\tt _{86}^{222}Rn\Rightarrow _{84}^{218}+_2^4He[/tex]
1. The mass number of the daughter isotope = 218
2 and 3. If we look at the periodic system, the element with atomic number 84 is Polonium (Po)
Suppose you wanted to calculate the heat of reaction for the formation of ammonia gas and hydrochloric acid from solid ammonium chloride. Write a balanced equation for this reaction
Answer:
NH4Cl (s) → NH3 (g) + HCl (aq)
What kinds of paintings did Winslow Homer make
Which scientist did people think was insane so they dismissed his ideas for almost 2000 years?
A metal object has a density of 2 g/ml. When placed in a graduated cylinder with 500 ml of water, the
water rises to 508 ml. What is the mass of the metal object?
Answer:
The answer is 16 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volumeFrom the question
density = 2 g/ml
volume = final volume of water - initial volume of water
volume = 508 - 500 = 8 mL
We have
mass = 2 × 8
We have the final answer as
16 gHope this helps you
How do we balance Zn + HNO3 Zn(NO3)2 + NO + H20
3Zn + 8HNO₃⇒ 3Zn(NO₃)₂ + 2NO + 4H₂O
Further explanationEqualization of chemical reaction equations can be done using variables. Steps in equalizing the reaction equation:
1. gives a coefficient on substances involved in the equation of reaction such as a, b, or c etc. 2. make an equation based on the similarity of the number of atoms where the number of atoms = coefficient × index between reactant and product 3. Select the coefficient of the substance with the most complex chemical formula equal to 1For gas combustion reaction which is a reaction of hydrocarbons with oxygen produces CO₂ and H₂O (water vapor). can use steps:
Balancing C atoms, H and the last O atoms
Reaction
Zn + HNO₃⇒ Zn(NO₃)₂ + NO + H₂O
1. gives a coefficientaZn + bHNO₃⇒ Zn(NO₃)₂ + cNO + dH₂O
2. make an equationZn : left = a, right =1 ⇒a=1
H : left = b, right = 2d⇒ b=2d (eq 1)
N : left = b, right = 2+c⇒b=2+c (eq 2)
O : left = 3b, right = 6+c+d ⇒3b=6+c+d(eq 3)
From eq 1 and eq 33(2d)=6+c+d
6d=6+c+d
5d=6+c (eq 4)
From eq 2 and eq 33(2+c)=6+c+d
6+3c=6+c+d
2c=d (eq 5)
From eq 4 and eq 55(2c)=6+c
10c=6+c
9c=6
c = 2/3
input eq 5
d = 2 x 2/3
d = 4/3
input eq 1
b = 2 x 4/3
b = 8/3
The equation
aZn + bHNO₃⇒ Zn(NO₃)₂ + cNO + dH₂O to
Zn + 8/3HNO₃⇒ Zn(NO₃)₂ + 2/3NO + 4/3H₂O x 3
3Zn + 8HNO₃⇒ 3Zn(NO₃)₂ + 2NO + 4H₂O
The protons and neutrons are in the nucleus of the atom, while the electrons are on the outside. How would you calculate the number of neutrons in an atom? Subtract the atomic mass and the atomic number. Add the atomic mass and the atomic number. Subtract the number of protons from the atomic number. Add the number of protons to the atomic number.
Which components are part of all scientific investigations? Check all that apply.
Answer:
Steps of a scientific investigation include 1. make observation
2. ask a question
3. form a hypothesis
4. test the hypothesis
5. analyze results
5 , drawing conclusions,
6. and communicating the results
What volume will 250. mL of gas at STP occupy ig the pressure changes to 2.0 atmospheres and the temperature changes at 30 degrees Celsius
Answer:
it is 75 degrees
Explanation:
Volume is 138.7 mL.
The equation for calculation of volume is as follows:-
[tex]\frac{P_1V_1}{T_1} =\frac{P_2V_2}{T_2}[/tex]
STP:-
Temperature=273 K
Pressure=1 atm
[tex]\frac{1 atm\times250mL}{273 K} =\frac{2 atm\times V_2}{303\ K}\\V_2=138.7\ mL[/tex]
Hence, the volume is 138.7 mL.
To know more about:-
https://brainly.com/question/15988929
Which phrase describes density?
O height of a point above sea level
O force pushing on an area or a surface
O amount of mass in a certain volume
O amount of matter an object contains
Answer:
C: amount of mass in a certain volume
Explanation:
Just took the quiz and got 100%
If 23,000 joules of energy are used to heat mercury by 4.00 °C, what is the mass of the mercury?
The density of a pure liquid at 25 degrees Celsius was calculated by determining the mass and volume of a sample of the liquid. A student measured the mass of a clean, dry 25.00 mL volumetric flask, filled the flask to its calibration mark with the liquid, and then measured the mass of the flask and liquid. The recorded measurements are shown in the table above. On the basis of this information, to how many significant figures should the density of the liquid be reported?
Answer
The density of the liquid is 0.82 g/mL.
Explanation:
From the question given above, the following data were obtained:
Mass of empty flask = 18.990 g
Mass of flask + liquid = 39.439 g
Volume of liquid = 25 mL
Density of liquid =..?
Next, we shall determine the mass of the liquid. This can be obtained as follow:
Mass of empty flask = 18.990 g
Mass of flask + liquid = 39.439 g
Mass of liquid =.?
Mass of liquid = (Mass of flask + liquid) – (Mass of empty flask)
Mass of liquid = 39.439 – 18.990
Mass of liquid = 20.503 g
Finally, we shall determine the density of the liquid as follow:
Mass of liquid = 20.503 g
Volume of liquid = 25 mL
Density of liquid =..?
Density = mass / volume
Density of liquid = 20.503 / 25
Density of liquid = 0.82 g/mL
Which tissues and organs belong to the Musculoskeletal System?
8.
188 W
188
75
Re
+
74
The statement means that in every interaction, there is a pair of forces acting on the two interacting objects. The size of the forces on the first object equals the size of the force on the second object. The direction of the force on the first object is opposite to the direction of the force on the second object. Forces always come in pairs - equal and opposite action-reaction force pairs.
i dont get what it means by of touch
Answer:
So I don't know what do you mean by that, please be a little specific.
Explanation:
^^
How does an object's mechanical energy change as its speed (velocity) increases?
Answer:
The mechanical energy of the system increases, provided there is no loss of energy due to friction. The energy would transform to kinetic energy when the speed is increasing. The mechanical energy of the system remains constant provided there is no loss of energy due to friction.
Explanation:
What is the volume of 25.3 g of silver if the density of silver is 10.5 g/mL?
Answer:
MARK AS BRAINLIST
Explanation:
density = mass/volume
mass=25.3
density =10.5
10.5=25.3/v
v=25.3/10.5
=2.40
Which group on the periodic table ways to lose electrons?
Answer:
Elements that are metals tend to lose electrons and become positively charged ions called cations. Elements that are nonmetals tend to gain electrons and become negatively charged ions called anions. Metals that are located in column 1A of the periodic table form ions by losing one electron.
Explanation:
hope it helps!
Using the reaction below: 2 CO2(g) + 2 H2O(l) → C2H4(g) + 3 O2(g) ΔHrxn= +1411.1 kJ What would be the heat of reaction for this reaction? 0.5 C2H4(g) + 1.5 O2(g) → CO2(g) + H2O(l) ΔHrxn= ??? KJ Question 6 options: a) Not enough information is given b) -2822.2 kJ c) +1411.1 kJ d) -705.55 kJ e) -1411.1 kJ
Answer: d) -705.55 kJ
Explanation:
Heat of reaction is the change of enthalpy during a chemical reaction with all substances in their standard states.
[tex]2CO_2(g)+2H_2O(l)\rightarrow C_2H_4(g)+3O_2(g)[/tex] [tex]\Delta H=+1411.1kJ[/tex]
Reversing the reaction, changes the sign of [tex]\Delta H[/tex]
[tex]C_2H_4(g)+3O_2(g)\rightarrow 2CO_2(g)+2H_2O(l)[/tex]
[tex]\Delta H=-1411.1kJ[/tex]
On multiplying the reaction by [tex]\frac{1}{2}[/tex] , enthalpy gets half:
[tex]0.5C_2H_4(g)+1.5O_2(g)\rightarrow CO_2(g)+H_2O(l)[/tex][tex]\Delta H=\frac{1}{2}\times -1411.1kJ=-705.55kJ/mol[/tex]
Thus the enthalpy change for the given reaction is -705.55kJ
How does the work needed to lift an object and the gravitational potential energy of the object compare? OThey are equal. OThe work is greater. OThe work is less. OThe comparison dependş on the height.
○ they are equal
○ the work is greater
○ the work is less
○ the comparison depends on the height
Answer:
They are equal
Explanation:
took the test
Answer:
ITS A JUST FINISHED
Explanation:
You check the air pressure in your car tires on Monday morning and the pressure
reads 765 mmHg. A cold front drops the temperature considerably overnight. You
check your tire pressure Tuesday morning and the pressure reads 740 mmHg.
Using what you've learned about the properties of gases, what causes this change
in pressure?
Match the element with their place on the periodic table.
Question 4 options:
Period 4, group 5-
Period 5, group 7-
Period 7, group 5-
Period 5, group 4-
1. dubrium
2. technetium
3. zirconium
4. vanadium
Answer:
Period 4, group 5- Vanadium
Period 5, group 7- Technetium
Period 7, group 5- Dubnium
Period 5, group 4- Zirconium
Explanation:
Calculate the molarity of a NaOH solution that is prepared by diluting 100mL of 0.20M NaOH with 150mL of H2O.
Molarity of solution = 0.08 M
Further explanationMolarity shows the number of moles of solute in every 1 liter of solution or mmol in each ml of solution
[tex]\tt M=\dfrac{n}{V}[/tex]
Where
M = Molarity
n = number of moles of solute
V = Volume of solution
mol of NaOH[tex]\tt mol=0.2~M\times 100~ml=20~mlmol=0.02~mol[/tex]
molarityVolume of solution = 100 ml + 150 ml = 250 ml
[tex]\tt M=\dfrac{0.02~mol}{0.250~L}=0.08[/tex]
what part of the scientific method involves drawing inferences about experimental results and determining if the collected data support the original hypothesis?
Answer:
Drawing Conclusions
Explanation:
You put together your observations and can finally decide if your hypothesis was right or not.
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Hydrogen atoms are excited by a laser to the =4 state and then allowed to emit.
What is the maximum number of distinct emission spectral lines (lines of different wavelengths) that can be observed from this system? Calculate the wavelength of the 4⟶3 transition.
Answer:
1875 nm
Explanation:
Given the Rydberg formula for hydrogen: 1/λ = R(1/n₁² - 1/n₂²)
where R ≈ 1.097* 10^7 /m
Hence;
1/λ = 1.097* 107/m * (1/3² - 1/4²) = 5.3 * 10^5/m
λ = 1.875 * 10-6 m = 1875 nm
Which landform is created by glaciers? A. sandbar B. moraine C. alluvial fan (will give brainliest to the best answer)
Answer: B: Moraine
Explanation:
Un compuesto formado por carbono, hidrógeno y oxígeno tiene una masa de 4,6 g. Se hace reaccionar con 9,6 g de oxígeno dando 8,8 g de CO2 y 5,4 g de agua. Si cogemos 9,2 g de un compuesto en un volumen 5,80l en P= 780 mmHg a una temperatura de 90ºC. Calcula la fórmula empírica y molecular.
Answer:
La fórmula empírica y molecular es: C₂H₆O.
Explanation:
Para calcular la formula empírica y molecular del compuesto debemos primero plantear la reacción:
[tex] C_{x}H_{y}O_{z} + O_{2} \rightarrow CO_{2} + H_{2}O [/tex]
Necesitamos encontrar "x", "y" y "z". Para ello, tenemos que recordar que la masa de carbono e hidrógeno producida está relacionada con la cantidad de C y H inicial (del compuesto):
Para el H:
CHO → H₂O
y 5,4g
[tex] \frac{2*1 g}{18 g} = \frac{y}{5,4 g} \rightarrow y = 0,6 g [/tex]
Para C:
CHO → CO₂
x 8,8g
[tex] \frac{12 g}{44 g} = \frac{x}{8,8 g} \rightarrow x = 2,4 g [/tex]
Para el O:
[tex] z = 4,6 g - 2,4 g - 0,6 g = 1,6 g [/tex]
Ahora mediante el calculo de los moles del C, H y O podemos encontrar la fórmula empírica:
Para el H:
[tex] n_{y} = \frac{m}{Pm} = \frac{0,6 g}{1 g/mol} = 0,6 moles [/tex]
Para el C:
[tex] n_{x} = \frac{m}{Pm} = \frac{2,4 g}{12 g/mol} = 0,2 moles [/tex]
Para el O:
[tex] n_{z} = \frac{m}{Pm} = \frac{1,6 g}{16 g/mol} = 0,1 moles [/tex]
[tex] C_{\frac{n_{x}}{n_{z}}}H_{\frac{n_{y}}{n_{z}}}O_{\frac{n_{z}}{n_{z}}} = C_{\frac{0,2}{0,1}}H_{\frac{0,6}{0,1}}O_{\frac{0,1}{0,1}} = C_{2}H_{6}O_{1} [/tex]
Entonces, la fórmula empírica del commpuesto formado es C₂H₆O.
Ahora para determinar la fórmula molecular podemos usar la siguiente relación:
[tex] \frac{Pm}{Pm_{e}} = n [/tex]
[tex] F_{m} = n*F_{e} [/tex]
[tex] F_{m} = \frac{Pm}{Pm_{e}}*F_{e} [/tex]
En donde Fm (fórmula molecular) y Fe (fórmula empírica) están relacionadas por n.
El valor de Pm lo obtenemos de la ecuación del gas ideal:
[tex]PV = nRT = \frac{m}{Pm}RT[/tex]
[tex] Pm = \frac{mRT}{PV} = \frac{9,2 g*0,082 L*atm/(K*mol)*(90 + 273 K)}{1.02 atm*5,80 L} = 46,3 g/mol [/tex]
[tex] F_{m} = \frac{46,3 g/mol}{(2*12 + 6*1 + 16)g/mol}*C_{2}H_{6}O_{1} = 1.00*C_{2}H_{6}O_{1} = C_{2}H_{6}O_{1} [/tex]
Por lo tanto, la fórmula molecular es la misma que la fórmula empírica, a saber C₂H₆O.
Espero que te sea de utilidad!