Answer:
In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed. The distinction between physical and chemical change is not clear cut.
Please somone help me with a chemistry question brainliest to whoever answers correctly and 20 points
Answer:
342.15 g/mol
..........
A compound being used in experimental medicine is 78.14% boron (B) and 21.86% hydrogen (H). The empirical formula of the compound will have a boron to hydrogen ratio of
Explanation:
I did it step by step so It would be easier to understand:)
Hey everyone, I'm starting honors chemistry next year and I want to get prepared for the class. What are the basic keys information that I need to know for the subject.
Thanks!
Answer:
hi!
Explanation:
Well, some things I would do is to know the Periodic Table font and back. Know they elements and their class and atomic number and weight. Know how many atoms make up each element and how many protons, neutrons, and elements are in each atom.
A population of Esherichia coli is given time to grow for eight generations. The final population is 1,996,800 cells. What was the initial population in cells?
Answer:
7800 cells
Explanation:
The number of Escherichia coli cells N after n generations is given by
N = 2ⁿ × N₀ where N₀ = initial population
Now making N₀ subject of the formula, we have
N₀ = N/2ⁿ
Since n = 8 and N = 1,996,800 cells, substituting the values of the variables into the equation, we have
N₀ = N/2ⁿ
N₀ = 1,996,800 cells/2⁸
N₀ = 1,996,800 cells/256
N₀ = 7800 cells
So, the initial population of Escherichia coli cells is 7800 cells.
What factors generally determine whether a reaction happens or not?
A. Reaction rate and color
B. Presence of water and salt
C. Enthalpy and entropy
D. Keg and Ka
Answer:
Explanation:
The answer is C Enthaply and entropy because temperature plays a big role in reactions
Answer:
c
Explanation:
a p e x :)
What is the mass percentage of copper in a 250 g sample of brass. Brass is made of copper and zinc and copper content of the sample is 150 g
Answer:
Percentage of copper in sample = 60%
Explanation:
Given:
Mass of copper = 150 gram
Mass of brass = 250 gram
Find:
Percentage of copper in sample
Computation:
Percentage of copper in sample = [Mass of copper / Mass of brass]100
Percentage of copper in sample = [150/250]100
Percentage of copper in sample = [0.6]100
Percentage of copper in sample = 60%
Which process, in order, would be necessary for this sequence of the rock cycle:
rock → metamorphic rock → igneous rock
Heat and pressure → melting → cooling
Weathering and erosion → compaction → weathering and erosion
Melting → cooling → melting → erosion
Cooling → melting → cooling → weathering and erosion
Answer:
may be the answer is Heat and pressure - melting - cooling
What type of experiment did the student in the passage perform?
Answer:
Passage?
Explanation:
How many moles are in 2.11 x 1014 molecules of LiBr?
Answer: There are [tex]12.71 \times 10^{-9}[/tex] moles present in [tex]2.11 \times 10^{14}[/tex] molecules of LiBr.
Explanation:
According to the mole concept, there are [tex]6.022 \times 10^{23}[/tex] molecules present in 1 mole of a substance.
Hence, moles in [tex]2.11 \times 10^{14}[/tex] molecules of LiBr are calculated as follows.
[tex]Moles = \frac{2.11 \times 10^{14}}{6.022 \times 10^{23}}\\= 12.71 \times 10^{-9}[/tex]
Thus, we can conclude that there are [tex]12.71 \times 10^{-9}[/tex] moles present in [tex]2.11 \times 10^{14}[/tex] molecules of LiBr.
Considering the temperature vs. time graph below, how does the temperature at the beginning of a change of state
compare with the temperature at the end of the change?
Answer:
The temperature on the graph is higher at point 5 than at point 1. The correct answer is the last answer choice that you showed.
Explanation:
The temperature at point 1 is -10 degrees Celsius, while the temperature at point 5 is 120 degrees Celsius. This is a 1300% increase.
See the calculation here: https://www.calculatorsoup.com/calculators/algebra/percent-change-calculator.php?v_1=-10&v_2=120&action=solve
I hope this helps.
What is the mass of 0.251 moles of water? Using dimensional analysis show work
[tex]1 \text{ mol of H}_2 \text{O} \equiv 18 \text{ g} \implies 0.251 \text{ moles of H}_2 \text{O} \equiv 4.518 \text{ g}[/tex]
¡A que clasificación corresponden las sustancias que están formadas por un mismo tipo de átomos, es homogénea y no puede descomponerse por medios químicos?
Answer:
Elementos.
Explicación:
Los elementos son las sustancias puras que están formadas por el mismo tipo de átomos, es homogéneo y no se puede descomponer por medios químicos. El elemento tiene el mismo tipo de átomos que son similares en tamaño y forma. Es un tipo de materia pura que tiene solo un tipo de átomos y no se puede descomponer más porque no está hecha de dos sustancias, es solo una sustancia, por eso no se puede descomponer por medios químicos.
6. You have a sample of H2Ois, with a mass 23.0 grams at a temperature of 46.0
temperature water would be in what state? Use reference table on page 492 for specific heat
capacity of ice). How many kilojoules of heat energy are necessary to carry out each step? Also
calculate the total amount of energy needed.
a) heat the ice to 0.0 °C?
Answer: I think it would be -23
Explanation:
a reaction of heating patassium permanganate produces potassium manganate, manganese dioxide and oxygen gas. Heat 15.8 g potassium permanganate until no more oxygen gas is given off. The remaining material has a mass of 14.2 g. What mass of oxygen gas was produced in the reaction?
Will give Brainliest and 20 points
Answer:
k = 1.26 x 10^-12
Its extremely small.
It follows that when k is small... The equilibrium concentration of Reactant is large and More than Product.
Option C should be your answer
An inverse relationship can be represented by what?
Answer:
1/....
Explanation:
If we say acceleration 'a' is inversely proportional to mass 'm', then
a=1/m.
Pure hydrogen (H₂) is a hazardous substance. Thus, safer and more cost effective techniques have been developed to store it as a solid for shipping purposes. One such method is the reaction below, which occurs at 200 °C.
Answer: hello your question has some missing details attached below is the missing details
answer : 25.5% ( B )
Explanation:
Determine percentage yield
molar mass = 35 g/mol
mass of Li₃N(s) = 70 g
product LiH(s) = 8.0 g ( actual yield )
theoretical yield ( LiH ) = 4 * 7.95 = 31.8 g
percentage yield = actual yield * 100 / theoretical yield
= 8 * 100/31.8
= 25.5%
how many moles are in 20 grams of argon
Answer:
There are 0.5 mole in 20g of argon.
Explanation:
40 g of argon = 1mole
Then 20g of argon is,
→ 1/40 × 20
→ 0.5 mole
Answer:
[tex]n = \frac{mass}{molar \: mass} \\ n = \frac{20g}{39.948 \frac{g}{mol} } \\ n = 0.5 \: mol \: of \: argon[/tex]
Explanation:
hope this makes sense
:)
Help!! Please explain how you get the answer
Answer:
5 moles
Explanation:
First, write out the balanced equation:
2Al + Fe₂O₃ → Al₂O₃ + 2Fe
Reaction ratio of Al to Fe₂O₃ is:
2 : 1
This means 2 moles of Al will react with 1 mole of Fe₂O₃
Al: 5 mol
Fe₂O₃: 3 mol
Multiply the reaction to get moles of both reactants you have:
2 : 1 (×⁵/₂) = 5 : ⁵/₂
2 : 1 (×3) = 6 : 3
In other words, 5 moles of Al will react with ⁵/₂ moles of Fe₂O₃;
And 3 moles of Fe₂O₃ will react with 6 moles of Al;
But, we do not have 6 moles of Al, therefore only the 5 moles of Al available will react;
5 moles of Al reacts with ⁵/₂ moles of Fe₂O₃, as we can see from the ratios we calculated above, the remaining ¹/₂ mole of Fe₂O₃ will not react;
We say that Al is the limiting reactant because all the Al will react but all the Fe₂O₃ does not (i.e. it is in excess);
Next and last, the reaction ratio of Al to Fe is:
2 : 2 or, more simply 1 : 1
This means the moles of Al that reacts is the equal to the moles of Fe produced from the reaction;
We've established that 5 moles of Al will react with ⁵/₂ moles of Fe₂O₃, so 5 moles of Fe will also be produced (since the ratio is 1 : 1);
You could also work this out using the moles of Fe₂O₃ that react;
The reaction ratio of Fe₂O₃ to Fe:
1 : 2
So the moles of Fe produced is 2× the moles of Fe₂O₃;
If ⁵/₂ moles of Fe₂O₃ reacts, then simply multiply this by 2 which is 5 moles
hyy guys.... can you plz writ me a journal plz ..... connection with science... any topic will be done today is my submition
ur best try is to copy and paste and change some words.
*CAN SOMEONE HELP ME PLEASE*
Answer:
d
Explanation:
the answer is d is that correct
How many grams of calcium chloride would you measure if you needed to
add 0.125 moles of calcium chloride to 100mL of water?
Answer: cuhh
Explanation:
1. How many molecules of S2 gas are in 756.2 L?
a. 2.032 x 1025 molecules S,
b. 3.022 x 1023 molecules S,
c. 4.302 x 10 molecules S
d. 8.203 x 10' molecules S2
Answer: There are [tex]2.032 \times 10^{25}[/tex] molecules [tex]S_{2}[/tex] gas are in 756.2 L.
Explanation:
It is known that 1 mole of any gas equals 22.4 L at STP. Hence, number of moles present in 756.2 L are calculated as follows.
[tex]Mole = \frac{Volume}{22.4 L}\\= \frac{756.2 L}{22.4 L}\\= 33.76 mol[/tex]
According to mole concept, 1 mole of every substance contains [tex]6.022 \times 10^{23}[/tex] molecules.
Therefore, molecules of S present in 33.76 moles are calculated as follows.
[tex]1 mol = 6.022 \times 10^{23}\\33.76 mol = 33.76 \times 6.022 \times 10^{23}\\= 2.032 \times 10^{25}[/tex]
Thus, we can conclude that there are [tex]2.032 \times 10^{25}[/tex] molecules [tex]S_{2}[/tex] gas are in 756.2 L.
The molar mass of copper(II) chloride (CuCl2) is 134.45 g/mol. How many formula units of CuCl2 are present in 17.6 g of CuCl2?
Answer:
7
Explanation:
took test
How much pressure should an airbag have?
Answer:
It should have about 70-80 pounds of air pressure.
Answer:
5 lbs is what I read on the internetluv </3
What happens to the hydrogen ion (H+) concentration as an aqueous
solution becomes more acidic? *
A)decreases
B)increases
C)remains constant
D)cannot be determined
Answer:
Explanation:
It can be determined by measuring the Ph. D is incorrect.
C: is wrong because if you are making something acidic, you are increasing the H+
B: is the correct answer.
A: pH decreases. H+ increases which makes the Ph decrease. It is an oddity of the formula that makes this happen.
which of these elements has two valence electrons?
a. hydrogen (H)
b. barium (Ba)
c. nitrogen (N)
d. krypton (Kr)
e. bromine (Br)
In explosive combustion the rapid expansion of --------------- causes explosion and the production of ------------------
Answer:
Volume; high temperature and pressure
Explanation:
In an explosive combustion the rapid expansion of the volume causes explosion and the production of high temperature and pressure.
The substance is usually in a confined place and the expansion usually reaches a breaking point in which it is expelled from the space usually accompanied with a loud noise and high amount of temperature and pressure change thereby releasing its gas constituents.
La columna de la izquierda corresponde a los tipos de sales y la columna derecha a los tipos de fórmula que presentan. Relacionar con el mismo COLOR las parejas correspondientes. 1. Hidracidas a. MX 2 Acidas b. MXO 3. Oxacidas c. MHXO 4. Basicas d. M(OH)XO
Answer:
1. Hidracidas a. MX
2 Acidas c. MHXO
3. Oxacidas b. MXO
4. Basicas d. M(OH)X
Explanation:
¡Hola!
En este caso, de acuerdo con el concepto de sal, la cual está generalmente dada por la presencia de al menos un metal y un no metal, es posible encontrar cuatro tipos de estas; hidrácidas, oxácidas, básicas y ácidas, en las que las primeras dos son neutras pero la segunda tiene presencia de oxígeno, la tercera tiene iones hidróxido adicionales y la cuarta iones hidrógeno de más.
Debido a la anterior, es posible relacionar cada pareja de la siguiente manera:
1. Hidracidas a. MX
2 Acidas c. MHXO
3. Oxacidas b. MXO
4. Basicas d. M(OH)XO
En las que M se refiere a un metal, X a un no metal, H a hidrógeno y O a oxígeno.
¡Saludos!
Describe the chemical reaction based on the chemical equation below. Also, explain whether the equation is balanced. NH3(g)+o2=NO(g)+H2O(I)
Answer:
2 moles of ammonia gas (NH₃) reacts with 5/2 moles of oxygen gas (O₂) to produce 2 moles of nitrogen monoxide gas (NO) and 3 moles of liquid water (H₂O)
Explanation:
The chemical equation is:
NH₃(g) + O₂(g)⇒ NO(g) + H₂O(I)
First, we have to distinguish which are reactants and which are products.
Reactants ⇒ left side: NH₃ (ammonia gas) and O₂ (oxygen gas)
Products ⇒ right side: NO (nitrogen monoxide) and H₂O (water)
Thus, ammonia gas reacts with oxygen gas to produce nitrogen monoxide gas and liquid water.
The reaction is not balanced, because it does not has the same number of atoms of each chemical element in both sides. To balance, we have to write a coefficient of 3 for H₂O, then a coefficient of 2 for NH₃ (to balance H atoms), then a coefficient of 2 for NO, and finally a coefficient of 5/2 for O₂ (to obtain 5 atoms of O in both sides):
2 NH₃(g) + 5/2 O₂(g)⇒ 2 NO(g) + 3 H₂O(I)
According to the balanced equation, 2 moles of ammonia gas (NH₃) reacts with 5/2 moles of oxygen gas (O₂) to produce 2 moles of nitrogen monoxide gas (NO) and 3 moles of liquid water (H₂O).