A substance changes from a solid to a liquid at its
Answer:
Melting point
Explanation:
Answer:
Melting point
Explanation:
When a solid turns into a liquid, it is melting. Therefore, it is the melting point.
Can someone help me with this chemistry question?
(This isn't the question but I need some help, I'll give 50 points to whoever can correctly answer my next question)
Answer:
We can't see the question. Can you upload a picture of it or write the question in the comments
KK
Which chemistry question?
the length of a string is 16cm.Its length becomes 20cm when supporting a weight of 5N.Calculate the length of the string when supporting a weight of 6N.Comment on the answer
Answer:
[tex]20.8cm[/tex]Explanation:
According to hooks law "provide the elastic limit of an elastic material is not exceeded the extension e is directly proportional to the applied force F"
[tex]F= ke[/tex]
where F= applied force
k= spring constant
e= extension
Given data
length of string l = 16cm
extension e = 20-16= 4cm
applied force = 5N
we need t o first calculate the spring constant k
apply the formula
[tex]F= ke[/tex]
[tex]5=k*4\\k= \frac{5}{4} \\k= 1.25N/cm[/tex]
we can now calculate the extension of the string when supporting a 6N weight
[tex]F= ke\\6=1.25*e\\e= \frac{6}{1.25} \\e= 4.8cm[/tex]
The length of the string when supporting a 6N weight is
[tex]= length+ extension\\= 16+4.8\\= 20.8cm[/tex]
COMMENT :According to the analysis an extra weight of 1N will cause add 0.8cm to the length of the string
The number of molecules in 1 mole of NaCl?
Answer:
6.022 x 10^23 molecules
Explanation:
Explain why carbon is able to form such a large number of compounds and describe several different types of hydrocarbon compounds.
Answer:
Carbon is the only element having the ability to form large numbers of compounds because carbon atom has four electrons in its valence shell and can share not only one but more electrons with other atoms and can form four chemical bonds which results into huge number of hydrocarbons.
Different types of hydrocarbons are:
Methane - it has only one carbon bounded with four hydrogen atoms with single bond and have chemical formula CH4.
Ethane: it has two carbon atoms attached with single bond and bounded with three hydrogen atoms each with single bond and have chemical formula C2H6.
Ethene: it has two carbon atoms attached with double bond and bounded with two hydrogen atoms each with single bond and have chemical formula C2H4.
Butyne: it has four carbon atoms, two of which are attached with triple bond and rest electrons are attached with hydrogen atoms and have chemical formula C4H6.
Hence, carbon is able to form such a large number of compounds.
When may a scientific theory be revised
Answer:
A theory doesn’t change into a scientific law because of new or better evidence.
Explanation:
A theory will always remain a theory, and i law will remain a law. The reason being that theories and laws may differ on account of newfound countervailing evidence. Remember, theories and laws are very different from hypotheses.
How can scientists use data to predict changes in
the shape of the Earth?
How Do You Get Different Coloured Fireworks? ...
Which is most likely to influence the properties of an element? *
-its atomic mass
-its atomic number
-the number of outer electroms
-the number of isotopes
Answer:
-the number of outer electrons
Explanation:
Outer electrons are referred to as valence electrons and they are typically what determines the property of an elements such as their reactivity.
For eg, Na (sodium) has 1 valence electron and it really wants to give it aways so it can return back to octet rule (having 8 electrons in outershell) to become stable. So when you put sodium in water (you can watch videos of it) it literally blows because of high reactivity.
How much heat is required to change temperature of 2g of water from 34°C to 68°C? (Water has a specific heat of 4.18)
a) 852.7 joules
b) 284.2 joules
c) 2 joules
d) -284.2 joules
Answer: B
Explanation:
To find the amount of heat required, you would use q=mcΔT.
[tex]q=2g(4.18J/g°C)(68-34°C)[/tex]
q=284.2 J
*Please ignore the capital A in the equation. I can't find a way to type in the degree sign into the equation without the A appearing.
Select the correct order of evaporation for water, alcohol, petrol and kerosene oil:- A. Petrol > alcohol > water > kerosene oil B. Alcohol > petrol > water > kerosene oil C. Water > alcohol > kerosene oil > petrol D. Petrol > alcohol > kerosene oil > water
Answer:
The correct option is;
D. Petrol > Alcohol > Kerosene oil > Water
Explanation:
The volatility of a liquid is a measure of how readily it evaporates or vaporizes such that a volatile liquid will evaporate and be present as a vapor at a given temperature or pressure than a less volatile liquid
The volatility of a liquid is directly related to the liquid's vapor pressure such that the higher the vapor the more volatile the liquid
The Reid vapor pressures of the given liquids are as follows;
Alcohol (Ethanol)= 17-55 kPa
Petrol = 53-60 kPa
Kerosene Oil= 6.8 kPa
The vapor pressure for water at 37.8°C = 6.6 kPa
Therefore, the correct order evaporation is as follows, starting from the highest vapor pressure to the lowest;
Petrol > Alcohol > Kerosene Oil > Water.
5. A gas at 127०C and 10.0 L expands to 20.0 L. What is the new temperature in Celcius? (HINT: You need to convert to Kelvins solve then convert answer back to ०C)
Answer:
The new temperature is 527.15 ºC.
Explanation:
Charles’s law states that the volume of a fixed amount of gas maintained at constant pressure is directly proportional to the absolute temperature of the gas (the absolute temperature is the Kelvin temperature).
We need to calculate the temperature after the expansion, that is T₂. For that, we use Charles' law:
[tex] V₁ ÷ T₁ = V₂ ÷ T₂ [/tex]
Because we have to use the absolute temperature, we convert ºC to K adding 273.15:
T₁ = 127 ºC + 273.15 ºC = 400.15 K
[tex] T₂ = V₂ × T₁ ÷ V₁ [/tex]
[tex] T₂ = 20. 0 L × 400.15 K ÷ 10.0 L [/tex]
T₂ = 800.3 K
We substract 273.15 to the result to convert it back to ºC:
T₂ = 800.3 - 273.15 = 527.15 ºC.
rust is an oxide of _____
Answer:
iron
Explanation:
rust is an oxide of iron
Scientific predictions should be made from:
a) deductive reasoning
b) inductive reasoning
c) presuppositions
d) subjective reasoning
Answer:
b) Inductive Reasoning
Explanation:
The immune system consists of two main parts or system. One system works 24/7 and protects your regardless of what type of microorganism is encountered. This system is called the ______________________ system. The other system requires recognition of the invader to react and begin to fight back an infection. This is called the __________________________ system.
Answer:
Innate immune system Acquired immune systemExplanation:
The innate immune system is a defense system with which we are all born and which protects us at all times against all antigens, prevents harmful external bodies from entering our body.
The acquired immune system is the second line of defense and develops by exposing itself to various antigens, building a defense against it when the innate system cannot fight the invader.
Answer:
Part A. The Innate immune system
Part B. The adaptive (or active) immune system
Explanation:
The immune system refers to the organs, tissues cells and proteins which work together to protect the body from harmful invaders that cause disease such as micro-organisms like viruses, bacteria, etc.
Organs and tissues that form part of the immune system include the thymus and bone marrow, lymph nodes and vessels, spleen, and skin.
The main immune cells are the white blood cells, also called leukocytes. Some types of white blood cells, called phagocytes engulf invading organisms. Others called lymphocytes help the body remember the invaders and destroy them. The two kinds of lymphocytes are B lymphocytes and T lymphocytes, whose name depend on where they mature. Lymphocytes start their life in the bone marrow and either stay there and mature into B cells, or go to the thymus gland to mature into T cells.
The immune system consists of two main parts or system.
Innate immunity: This refers to the immunity one is born with. Innate (or natural) immunity, provides a general type of protection. For example, the skin acts as a barrier to block germs from entering the body. Adaptive (or active) immunity: This refers to the immunity one develops throughout their lives. It is developed when one is exposed to diseases or when one is immunized against them with vaccines.Según la Organización Mundial de la Salud, el nitrato de plata ( densidad = 4.35 g/cc ) es una sustancia con propiedades cáusticas, astringente, antiséptica y antiinfecciosa que apenas puede absorberse por la piel. Calcular la cantidad de agua necesaria para preparar 800 mL de una disolución 2 M de nitrato de plata. Ayuda porfavor
Answer:
737.52 mL de agua
Explanation:
En este caso solo debes usar la expresión de molaridad de una solución la cual es:
M = moles / V
Donde:
V: Volumen de solución.
Como queremos saber la cantidad de agua, queremos saber en otras palabras cual es la cantidad de solvente que se utilizó para preparar los 800 mL de disolución.
Una disolución se prepara con un soluto y solvente. El soluto lo tenemos, que es el nitrato de plata. Con la expresión de arriba, calculamos los moles de soluto, y luego su masa. Posteriormente, calculamos el volumen con la densidad, y finalmente podremos calcular el solvente de esta forma:
V ste = Vsol - Vsto
Primero calcularemos los moles de soluto:
moles = M * V
moles = 2 * 0.800 = 1.6 moles
Con estos moles, se calcula la masa usando el peso molecular reportado que es 169.87 g/mol:
m = moles * PM
m = 1.6 * 169.87 = 271.792 g
Ahora usando el valor de la densidad, calcularemos el volumen de soluto empleado:
d = m/V
V = m/d
V = 271.792 / 4.35
V = 62.48 mL
Finalmente, la cantidad de agua necesaria es:
V agua = 800 - 62.48
V agua = 737.52 mL
a natural gas stove converts ... energy from burning into ... energy used to cook food.
Answer:
A natural gas stove converts chemical energy from burning into thermal energy used to cook food.
Why are bacteria are able to evolve rapidly
Carbon dioxide gas at a temperature of 35.0 C and a volume of 281mL. Determine the volume of the gas when the temperature of the gas is raised to 125 C if the pressure remains constant.
Answer: The volume of the gas when the temperature of the gas is raised to [tex]125^0C[/tex] is 363 ml
Explanation:
To calculate the final volume of the system, we use the equation given by Charles' Law. This law states that volume of the gas is directly proportional to the temperature of the gas at constant pressure.
Mathematically,
[tex]\frac{V_1}{T_1}=\frac{V_2}{T_2}[/tex]
where,
[tex]V_1\text{ and }T_1[/tex] are the initial volume and temperature of the gas.
[tex]V_2\text{ and }T_2[/tex] are the final volume and temperature of the gas.
We are given:
[tex]V_1=281ml\\T_1=35.0^oC=(35.0+273)K=308K\\V_2=?\\T_2=125^0C=(125+273)K=398K[/tex]
Putting values in above equation, we get:
[tex]\frac{281}{308}=\frac{V_2}{398}\\\\V_2=363ml[/tex]
Thus the volume of the gas when the temperature of the gas is raised to [tex]125^0C[/tex] if the pressure remains constant is 363 ml
What is the volume of .00831 mol of gas under ideal conditions if the
pressure is 1.01 atm and the temperature is 25 degrees C?*
Answer:
Approximately [tex]0.20\; \rm L[/tex].
Explanation:
Convert the temperature of this gas to absolute temperature:
[tex]T = 25\; \rm ^\circ C \approx (25 + 273.15)\; \rm K = 298.15\; \rm K[/tex].
Let [tex]P[/tex] and [tex]V[/tex] represent the pressure and volume of this gas, respectively. Let [tex]n[/tex] represent the number of gas particles in this gas. Let [tex]R[/tex] represent the ideal gas constant. By the ideal gas law:
[tex]P \cdot V = n \cdot R \cdot T[/tex].
For this question:
[tex]P = 1.01\; \rm atm[/tex] (given,) [tex]T = 298.15\; \rm K[/tex] (from unit conversion,) and[tex]n = 0.00831\; \rm mol[/tex].Look up the ideal gas constant [tex]R[/tex] that takes [tex]\rm atm[/tex] as the unit for pressure:
[tex]R \approx 0.082057\; \rm L \cdot atm \cdot K^{-1}\cdot mol^{-1}[/tex].
This question is asking for [tex]V[/tex], the volume of this gas. Rearrange the ideal gas equation and solve for [tex]V[/tex]:
[tex]\begin{aligned} V &= \frac{n \cdot R \cdot T}{P} \\ &\approx \frac{0.00831\; \rm mol\times 0.0082057\; \rm L \cdot atm \cdot K^{-1}\cdot mol^{-1}\cdot 298.15\; \rm K}{1.01\; \rm atm} \\ &\approx 0.0020\; \rm L\end{aligned}[/tex].
Iron will most likely react with which of the following elements?
uranium (U)
bromine (Br)
vanadium (V)
manganese (Mn)
Answer:
bromine (Br)
Explanation: Iron enters into a reaction with substances of different classes, and interacts with oxygen, carbon, phosphorus, halogens (bromine, iodine, fluorine and chlorine), and also nitrogen. These are not all the reactions of iron – this metal reacts with many elements.
4.AsampleoffruithasapHof4.2.Whatistheconcentrationinmoldm-3ofhydroxideions, [OH -]inthejuice?A.1.58x10 -5 B.1.58x10 -10 C.6.31x10 -5 D.9.80x10
Answer: B. 1.58 x 10 ∧ -10 mol/dm3 of OH- ions
Explanation:
pOH = - log [OH-]
It is well known that; pH + pOH = 14
That is to say; 4.2 + pOH = 14, therefore; pOH = 14 - 4.2 = 9.8
9.8 = - log [OH-]
In other to get the concentration, we take the anti-log of 9.8 .
Anti-log of 9.8 = 1.58 x 10 ∧ -10mol/dm3.
14. Acid + Metal carbonate:?
a. Salt + water + carbon dioxide
b. Salt + carbon dioxide
c. Salt + water + hydrogen
d. Salt + hydrogen
Answer:
The answer is A.
Explanation:
When acid react with metal carbonate, it will form salt, water and carbon dioxide.
For example :
HCl + CaCO3 → CaCl + H2O + CO2
what is the new temperature when 10 L at 5 K is compressed to 4.00 L
a) 20 K
b) 25 K
c) 2 K
d) 0.5 K
Answer: C
Explanation:
For this problem, we would use Charles's Law. We fill in what we are given and solve.
Charles's Law: [tex]\frac{V_{1} }{T_{1} } =\frac{V_{2} }{T_{2} }[/tex]
[tex]\frac{10 L}{5K} =\frac{4.00L}{T_{2} }[/tex]
[tex]10T_{2}= 20[/tex]
[tex]T_{2}=2K[/tex]
heat transfer between two systems only occurs if there is a
Answer: thermal equilibrium
Explanation: the temperature increased only when all of the water was in one phase.
are computers capable of inductive reasoning
What gas comes off it
Answer:
the answer to this question is hydrogen gas
Calcium carbonate decomposes at 12000 C to form carbon dioxide and calcium oxide. If 25 liters of carbon dioxide are collected at 12750 C, what will the volume of this gas be after it cools to 250 C?
Answer:
1L
Explanation:
Data obtained from the question include:
Initial volume (V1) = 25L
Initial temperature (T1) = 12750°C
Final temperature (T2) = 250°C
Final volume (V2) =..?
Next we shall convert from celsius to Kelvin temperature. This is illustrated below:
T(K) = T(°C) + 273
Initial temperature (T1) = 12750°C
Initial temperature (T1) = 12750°C + 273 = 13023K
Final temperature (T2) = 250°C
Final temperature (T2) = 250°C + 273 = 523K
Finally, we can obtain the new volume of the gas by using Charles' law equation as shown below:
V1/T1 = V2/T2
25/13023 = V2/523
Cross multiply to express in linear form
13023 x V2 = 25 x 523
Divide both side by 13023
V2 = 25 x 523 / 13023
V2 = 1L
Therefore, the new volume of the gas is 1L.
The volume of this gas after it cools to 250°C is equal to 0.490 Liter.
Given the following data:
Initial volume = 25.0 L Initial temperature = 12750°C Final temperature = 250°C
To determine the volume of this gas after it cools to 250°C, we would apply Charles's law:
Mathematically, Charles law is given by the formula;
[tex]\frac{V}{T} =k\\\\\frac{V_1}{T_1} = \frac{V_2}{T_2}[/tex]
Where;
T is the temperature of an ideal gas. V is the volume of an ideal gas.Substituting the given parameters into the formula, we have;
[tex]\frac{25}{12750} = \frac{V_2}{250} \\\\25 \times 250 = 12750V_2\\\\6250 = 12750V_2\\\\V_2 = \frac{6250}{12750}[/tex]
Final volume = 0.490 Liter.
Read more: https://brainly.com/question/22971882
Bronwyn completed the same chemical reaction four times. She weighed the amount of chemical produced by each experiment. Which result would show that the experiment is valid?
Answer:
If the weight of chemical is same so it represent that the experiment is valid.
Explanation:
If Bronwyn performed the same chemical reaction four times and she measure the weight of chemical with the help of electrical weight balance so if she find out the weight of the chemical that is produced during four experiments then we can say that the experiment is valid because the experiment was performed four times and that is enough for validation of the experiment.
Convert 300c into kelvin and Fahrenheit scale
Explanation:
300c = 1.8f+32= please calculate it yourself ☺
300c= k+273= 573k
