Answer:
The correct answer is pulsar.
Explanation:
Protostar : Its a young star with contracting mass which gains mass from its parent molecular cloud. At this stage fusion process does not start.
Red dwarf: A star having lower surface temperature , luminosity, mass and size than of the sun.
White dwarf : its an ultimate stage for an average mass star like sun . its a small dense star with size relatively equal to planet.
Pulsar : A rotating neutron star that emits beam of radio waves and other electromagnetic radiations.
Black hole: It is region of space time with very strong gravitational pull that even smallest particle or electromagnetic wave is incapable to escape it.
Answer:
3Pb(s) + 2H3PO4(l) →H3PO4 + Pb3(PO4)2 H2
Explanation:
I hope I helped you :P
CH 4 (g)+2O 2 (g) CO 2 (g)+2H 2 O(g)
Answer: combustion
Explanation:
Combustion reactions can be identified by looking at the reactants and the products.
Usually, the reactants will be a hydrocarbon and oxygen. And the products will be CO2 and H2O
Understanding the model of the atom helps predict how elements will react with each other.
For example, the ball-and-stick model is a molecular model of a chemical substance which is to display both the three-dimensional position of the atoms and the bonds between them.
The atoms are represented by spheres, connected by rods which represent the bonds.
Every ball represent one atom in one molecule and they have different colors for different atoms (for example, carbon is black, hydrogen is white, nitrogen is blue).
There also other models: skeletal models, polyhedral models, composite models, computer-based models.
To fully react with 750 g of HCl (approximately 20.5 moles), a minimum of 10.25 moles of sodium carbonate is needed.
To calculate the minimum amount of sodium carbonate needed to react fully with 750 g of HCl, we need to start by converting the 750 g of HCl to moles. The molecular weight of HCl is about 36.5 g/mol, so 750 g is about 20.5 mol of HCl. Looking at the reaction equation Na2CO3 + 2HCl → 2NaCl + CO2 + H2O, you can see that you need one mole of sodium carbonate to react with two moles of HCl. Therefore, to fully react with 20.5 mol of HCl, you will need a minimum of 10.25 mol of sodium carbonate.
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(1) CuO (3) Cu2O
(2) CuO2 (4) Cu2O2
Answer : The correct formula of copper(I) oxide is, (3)
Explanation :
Copper(I) oxide is an ionic compound because copper element is a metal and oxide element is a non-metal. The bond formed between a metal and a non-metal is always ionic in nature.
The nomenclature of ionic compounds is given by:
The charge on copper is (+1) and the the charge on oxide is (-2). The charges are not balanced. The charges are balanced by the criss-cross method.
Hence, the formula of copper(I) oxide is,
There are approximately 4.52 x 10^23 atoms in 0.750 moles of zinc.
To determine the number of atoms in a given amount of a substance, you can use Avogadro's number, which is approximately 6.022 x 10^23 atoms/mol.
Given that you have 0.750 moles of zinc, you can calculate the number of atoms using the following steps:
Multiply the given number of moles by Avogadro's number:
0.750 moles * (6.022 x 10^23 atoms/mol) = 4.5165 x 10^23 atoms
Round the result to an appropriate number of significant figures:
Since the value given has three significant figures, the final answer should be rounded accordingly. Therefore, the number of atoms in 0.750 moles of zinc is approximately 4.52 x 10^23 atoms.
So, there are approximately 4.52 x 10^23 atoms in 0.750 moles of zinc.
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