Which chemical equation best illustrates the Law of Conservation of Mass? (My answer: D)2H2O yields H2 + O2
CH4 + 3O2 yields CO2 + 2H2O
Al4C3 + 3H2O yields CH4 + 4Al(OH)3
Zn + 2HCl yields ZnCl2 + H2
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Related Questions
How many moles of H2 are needed to react with 1 mole off N2?
A is a heterogeneous mixture in which the particles settle to the bottom.
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CHEMISTRYWhich of the following properties of an element is least likely to change with beta decay? A. the mass number B. the period number C. the atomic number D. the name of the element When a nucleus has too many protons, it can absorb an electron and create _________. A. a proton B. a neutron C. an electron D. an alpha ray Which of the following occurs in beta decay? A. A neutron of an atom emits a high energy proton. B. A neutron of an atom emits a high energy electron. C. An electron of an atom emits a high energy proton. D. A neutron of an atom emits a second high energy neutron. What kind of ray is given off after electron capture? A. a beta ray B. a delta ray C. an alpha ray D. a gamma ray
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A. Stomach
B. Cook
C. Organ
D. Food
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Answer:
The correct answer is A. Stomach
Explanation:
The prefix gastro- is derived from the Greek word gastrós or gaster wich means stomach, the organ responsible for digestion of food. The most common examples are:
- Gastrointestinal: related to stomach and intestines
- Gastritis: inflammation of the stomach
- Gastroenteritis: inflammation of both stomach and intestines
A combining form with the meaning "stomach," is often used to create compound words, such as gastrology. Here the root word gastro means Stomach. The correct option is A.
The stomach is a muscular bag-like organ that is located on the left side of the upper abdomen. The esophageal sphincter, a valve, is used by the oesophagus to transfer food to the stomach. Acid and digestive enzymes are produced in the stomach to aid in meal digestion.
Storing and digesting the food and liquid consumed during meals is the stomach's main job. In order to aid in the digestion of food and other external items like germs, it creates hydrochloric acid and enzymes.
Thus the correct option is A.
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Here’s how you solve the problem.Calculate the volume of the unit cell.
If the length of an edge of the cell is a, then V = a³.
V = (385 × 10⁻¹² m)³ = 5.71 × 10⁻²⁹ m³Use the density to calculate the mass of the unit cell (The density of TlCl is the same, no matter what volume of TlCl we have).
Mass = 5.71 × 10⁻²⁹ m³ × (7.00 g/1 cm³) × (100 cm/1 m)³ = 3.99 × 10⁻²² gUse the molar mass to convert grams to moles.
3.99 × 10⁻²² g × (1 mol/239.8 g) = 1.67 × 10 ⁻²⁴ molUse Avogadro’s number to calculate the number of formula units.
1.67 × 10 ⁻²⁴ mol × (6.022 × 10²³ formula units/1 mol) = 1.00 formula units
Therefore, 1 unit cell of TlCl contains 1 formula unit.
Final answer:
To determine the formula units in a unit cell, understand the type of the unit cell structure (simple cubic, body-centred cubic, or face-centred cubic) and apply the appropriate calculation for that type.
Explanation:
To determine the number of formula units in a unit cell, one must first understand what these terms mean. A unit cell is the smallest repeating unit of a crystal lattice. There exist several different types that affect formula unit arrangement and quantity, including simple cubic, body-centred cubic, and face-centred cubic.
A crystal lattice is a three-dimensional framework of atoms, ions, or molecules arranged in a repeating pattern. The formula unit is the lowest whole-number ratio of ions represented in an ionic compound. In a simple cubic unit cell, there's one formula unit, in a body-centred cubic cell, there are two, and in a face-centred cubic cell, there are four.
For instance, if you are dealing with a simple cubic arrangement the unit cell is composed of 8 atoms forming the vertices and each one is shared amongst 8 neighbouring cells, you have (8 x 1/8 = 1) formula unit per cell. Similarly, in a body-centred cubic, there is 1 atom in the centre fully inside, and 8 on the corners shared with neighbouring cells, hence (1 + 8 x 1/8 = 2) formula units per unit cell.
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Transmission Electron microscope (TEM):a beam of electrons is passed through a thin section of specimen that is stained with atoms or heavy metals and electromagnets acts as lenses that focus the image onto a screen or film. It is used to study the internal structure of a specimen--cells
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Half life of the given radioactive substance after 1000 years is 500 years.
What is half life?
Half -life of a substance is defined as the time which is required for half of the quantity of a radioactive substance to get decayed.It is a term which is used in nuclear chemistry for describing how quickly unstable atoms undergo radioactive decay into other nuclear species by emitting particles or the time which is required for number of disintegrations per second of radioactive material to decrease by one half of its initial value.
For the given problem, T=1000 years and N=25% of N°
where T=time period , N=amount of quantity after decay ,N°= initial quantity.
Here,N=25% of N°
N=25/100 N°=N°/4
N°/4=N°/2
n=2
∵nt=T
So. 2t=1000
t=500 years.
Hence, the half-life of a substance is 500 years.
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25% means that 2 half-lives have already passed. So one half-life is 500 years.
b....32.6°C
c....115°C
d...388°C
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Gay-Lussacs law states that pressure of a gas is directly proportional to temperature when the volume is kept constant
P / T = k
where P - pressure , T - temperature in kelvin and k - constant
where parameters for the first instance are on the left side of the equation and parameters for the second instance are on the right side of the equation
T1 - 25 °C + 273 = 298 K
substituting the values in the equation
T2 = 388 K
temperature in celcius - 388 K - 273 = 115 °C
answer is C. 115 °C