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3 years ago

Please answer these 2 questions

Chemistry

1 answer:

My name is Ann [436]3 years ago

4 0

Answer:

Question 8, I think is C describe CR. Question 7 is Chemical reactions produce new substances

Explanation:

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Students conduct an experiment:

sweet-ann [11.9K]

Answer:

The balloon becomes inflated

Explanation:

The equation of the reaction between baking soda (sodium bicarbonate) and vinegar(ethanoic acid) is shown below;

NaHCO3 + HC2CH3O2 ------> NaC2H3O2 + H2O + CO2

The gas (CO2) evolved in the process leads to the inflation of the balloon dropped on the bottle in which the reaction is taking pace.

This observation provides evidence that a gas was really evolved in the reaction.

7 0

3 years ago

Fill in the coefficients that will balance the following reaction:

Alex17521 [72]

Answer:

To balance a reaction, the amount of reactants must be equal to the amount of products, as stated by the Law of Conservation of Matter. It may help you to keep track of the number of each element in a list as you try to balance. It's not able to be balanced.

3 0

3 years ago

Read 2 more answers

What is the nuclear binding energy for thorium-234? 2.78 × 10-10 J 3.36 × 10-14 J 1.67 × 1017 J 5.35 x 10-23 J

grin007 [14]

The correct option is A.
To calculate the binding energy, you have to find the mass defect first.
Mass defect = [mass of proton and neutron] - Mass of the nucleus
The molar mass of thorium that we are given in the question is 234, the atomic number of thorium is 90, that means the number of neutrons in thorium is
234 - 90 = 144.
The of proton in thourium is 90, same as the atomic number.
Mass defect = {[90 * 1.00728] +[144* 1.00867]} - 234
Note that each proton has a mass of 1.00728 amu and each neutron has the mass of 1.00867 amu.
Mass defect = [90.6552 + 145.24848] - 234 = 1.90368 amu.
Note that the unit of the mass is in amu, it has to be converted to kg
To calculate the mass in kg
Mass [kg] = 1.90368 * [1kg/6.02214 * 10^-26 = 3.161135 * 10^-27
To calculate the binding energy
E = MC^2
C = Speed of light constant = 2.9979245 *10^8 m/s2
E = [3.161135 * 10^-27] * [2.9979245 *10^8]^2
E = 2.84108682069 * 10^-10.
Note that we arrive at this answer because of the number of significant figures that we used.
So, from the option given, Option A is the nearest to the calculated value and is our answer for this problem.

8 0

3 years ago

Read 2 more answers

Elements occur in a number of isotopic forms. In this problem, you will learn about the notation used to distinguish different i

alina1380 [7]

Answer:

Number of protons, Z = 14
Number of neutrons, N = 14

Explanation:

1) About isotopes:

Isotopes are different kind of atoms of the same element. Hence, they have the atomic number (Z), which is the number of protons, the same number of electrons (talking about to neutral atoms, not ions), and different number of neutrons N).

This is, it is the number of neutrons what distinguish different isotopes of an element.

2) About the notation used to distinguish different isotopes:

A superscript and a subscript, both to the left of the chemical symbol of the element, are used to distinguish different isotopes:

A ←------------- This superscript tells the mass number of the isotope

X ←--------- This is the chemical symbol of the element

Z ←-------------- This subscript is the atomic number of isotope

In our case, the notiation for the isotope of silicon is: ²⁸₁₄ Si

So, we have:

28 is the mass number (A)
14 is the atomic number (Z)
Si is the chemical symbol.

Now, you can answer the questions of the part A:

Number of protons: Z = 14

Number of neutrons N:

mass number = number of protons + number of neutrons

A = Z + N

⇒ N = A - Z = 28 - 14 = 14

In conclusion:

Number of protons, Z = 14
Number of neutrons, N = 14

5 0

3 years ago

In the combustion chamber of an engine, the initial volume is 450 cm3 at a pressure of 1.0 atmosphere. If the piston displaces 4

Alona [7]

Assuming that the contents of the chamber ar ideal gases. We can use the relation PV=nRT. At a constant temperature and number of moles of the gas the product of PV is equal to some constant. At another set of condition of temperature, the constant is still the same. Calculations are as follows:

P1V1 =P2V2

P2 = (1)(450)/ 48

P2 = 9.375 atm

3 0

3 years ago