grade 8 chem/ science

Answer:

9x +6b

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Explanation:

Answer:

ssaasasasassdsdsdafdftrga*b*y/a la 3

Explanation:

Answer:

a) the number of protons in an atom

b) 11 protons, 11 electrons and 12 neutrons.

c) Isotope

d) yes, they still have the same number of protons and electrons.

Explanation:

b) Number of neutrons = mass number - atomic number

Atoms have the same number of electrons and protons

c) isotopes are atoms with the same number of  protons but a different number of neutrons.

Hope this helped !

Answer:

312.5 mL

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

HNO₃ + NaOH —> NaNO₃ + H₂O

From the balanced equation above,

The mole ratio of acid, HNO₃ (nₐ) = 1

The mole ratio of base, NaOH (n₆) = 1

Finally, we shall determine the volume of the base, NaOH needed for the reaction. This can be obtained as follow:

Molarity of base, NaOH (M₆) = 0.08 M

Volume of acid, HNO₃ (Vₐ) = 125 mL

Molarity of acid, HNO₃ (Mₐ) = 2 M

Volume of base, NaOH (V₆) =?

MₐVₐ / M₆V₆ = nₐ/n₆

2 × 125 / 0.80 × V₆ = 1/1

250 / 0.80 × V₆ = 1

Cross multiply

0.80 × V₆ = 250

Divide both side by 0.8

V₆ = 250 / 0.8

V₆ = 312.5 mL

Thus, the volume of the base, NaOH needed for the reaction is 312.5 mL

Answer:

false it's 24 hours long.

Answer:

pH = 3.0 ya that's it......

Answer:

A. Heat flows from block 1 to block 2

Explanation:

Thermal or heat energy flows when objects of different temperature come in contact. Heat naturally flows from hot objects (high temperature) to cold objects (low temperature) and will keep on flowing until an equilibrium is reached.

According to this question, two blocks of metal, which are of different temperatures, are illustrated to be in contact. Block 1 is at 60°C while Block 2 is at 25°C. Block 1 is hotter than Block 2, hence, heat will flow from block 1 to block 2.

Answer:

B. The League of Nations condemned the violations but took no other action.

Explanation:

Nazi leader, Adolf Hitler violated the Treaty of Versailles by sending German military forces in Rhineland. He not only violated the Treaty of Versailles but the Locarno Pact also.

The treaty was signed in 1919 to end the war between Germany and the Allied Powers.

Even after Adolf Hitler violated the treaty, the League Nations did not take any actions.

Therefore, option B is correct.

Answer:

Uranium-235 absorbing a neutron and breaking into Barium-141,  Krypton-92 and three neutrons

Explanation:

A fission reaction is said to have occurred when an unstable nucleus is bombarded with a neutron such that it disintegrates into daughter nuclei and produces more neutrons in the process. Hence, Uranium-235 absorbing a neutron and breaking into Barium-141,  Krypton-92 and three neutrons is a fission reaction.

This fission reaction is often a self sustaining reaction. The neutrons produced in the reaction bombards more of the parent nucleus and the process continues indefinitely(chain reaction).

Control rods and moderators are used to keep the chain reaction in check.

Answer:

94.2 g/mol

Explanation:

Ideal Gases Law can useful to solve this

P . V = n . R . T

We need to make some conversions

740 Torr . 1 atm/ 760 Torr = 0.974 atm

100°C + 273 = 373K

Let's replace the values

0.974 atm . 1 L = n . 0.082 L.atm/ mol.K . 373K

n will determine the number of moles

(0.974 atm . 1 L) / (0.082 L.atm/ mol.K . 373K)

n = 0.032 moles

This amount is the weigh for 3 g of gas. How many grams does 1 mol weighs?

Molecular weight → g/mol → 3 g/0.032 moles = 94.2 g/mol

Answer:

[tex]238.5gCuSO_4[/tex]

Explanation:

Hello there!

In this case, by considering the given chemical reaction, it is possible for us to calculate the required grams of CuSO4 by considering its molar mass of 159.6 g/mol, the given molecules of NaBr, the Avogadro's number and the 1:2 mole ratio between these two in order to set up the following stoichiometric set up:

[tex]1.80x10^{24}moleculesNaBr*\frac{1molNaBr}{6.022x10^{23}molecules NaBr}*\frac{1molCuSO_4}{2molNaBr} *\frac{159.6gCuSO_4}{1molCuSO_4}\\\\=238.5gCuSO_4[/tex]

Best regards!

Answer:

The state with the lowest possible energy consistent with the state of maximum disorder

so letter A

If a system is left to change spontaneously then, the state with the lowest possible energy is consistent with the state of maximum disorder. option A is correct.

A spontaneous change may be so fast or rapid or in a fraction of time that it is essentially instantaneous or fast or so slow that it cannot be observed over any practical time of  period.

A is the spontaneous change is one in which the system happening into which the  A an increase or boost  in internal energy B lowering  decline in entropy C lowering in energy D no energy change Medium.

The time-evolution  or change of a system in which it releases free energy and it moves to a lower, or decreased more thermodynamically stable energy state, closer to  attend the thermodynamic equilibrium.

Therefore, the system is left to change spontaneously then, and the state with the lowest possible energy is consistent with the state of maximum disorder. option A is correct.

Learn more about spontaneous change, here :

https://brainly.com/question/14437673

#SPJ2

Answer:

0.73 and yes

Explanation:

The answers are 0.73 and yes! <3 ^-^

Answer:

copper I oxide

Explanation:

Copper is known to form two oxides; copper I oxide and copper II oxide.

In the question we have the ions; Cu1+ and O2-. Ionic compounds are formed by a combination of ions as typified below;

Cu^+  +  O^2-   -------> Cu2O

This compound is copper I oxide

Explanation:

(Gases and liquids )

is the answer

Gases and liquids are the states of matter that have the same volume when moved.

Hope it helps you

Answer:

the changes are physical changes

Answer:

answer is A- nuclear fission is too hard to control for use in practical applications

Answer:

O C. Nuclear fission is used to produce electrical power.

Explanation:

Answer:

Assertion (A) is true

but reason (R) is false.

Explanation:

If we look at the assertion closely, it is true that a sublime substance changes from solid to gas without  passing through a liquid state. Naphthalene, camphor, iodine and ammonium  chloride are some common  examples of the substances  which undergo sublimation.

However, not all solids first pass through a liquid state before converting to gas. Sublime solids such as those listed above passes directly from solid to gas without passing through a liquid state.

Hence the assertion is true but reason is false.

Answer: 3.38 Atm is the partial ressure of each gas

Answer:

0.04 M.

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

Ba(OH)₂ + H₂SO₄ —> BaSO₄ + 2H₂O

From the balanced equation above,

The mole ratio of acid, H₂SO₄ (nₐ) = 1

The mole ratio of base, Ba(OH)₂ (n₆) = 1

Finally, we shall determine the molarity of Ba(OH)₂ solution. This can be obtained as follow:

Volume of base, Ba(OH)₂ (V₆) = 93.9 mL

Volume of acid, H₂SO₄ (Vₐ) = 15.3 mL

Molarity of acid, H₂SO₄ (Mₐ) = 0.247 M

Molarity of base, Ba(OH)₂ (M₆) =?

MₐVₐ / M₆V₆ = nₐ / n₆

0.247 × 15.3 / M₆ × 93.9 = 1/1

3.7791 / M₆ × 93.9 = 1

Cross multiply

M₆ × 93.9 = 3.7791

Divide both side by 93.9

M₆ = 3.7791 / 93.9

M₆ = 0.04 M

Therefore, the molarity of the Ba(OH)₂ solution is 0.04 M

Answer:

Explosive eruptions occur when magma, which is molten rock in the ground, contains gas. ... The most dangerous features of these events are volcanic ash flows  swift, ground-hugging avalanches of searing hot gas, ash and rock that destroy everything in their path.

Explanation:

Answer:

[tex]\boxed {\boxed {\sf 40.4299 \ Joules}}[/tex]

Explanation:

Potential energy is energy due to position. It is the product of mass, height, and acceleration due to gravity.

[tex]PE= m \times g \times h[/tex]

The mass of the textbook is 1.85 kilograms. Assuming this is on Earth, the acceleration due to gravity is 9.8 meters per square second. The height is 2.23 meters.

Substitute the values into the formula.

[tex]PE = 1.85 \ kg \times 9.8 \ m/s^2 \times 2.23 \ m[/tex]

Multiply the first 2 numbers together.

[tex]PE=18.13 \ kg*m/s^2 *2.23 \ m[/tex]

Multiply again.

[tex]PE= 40.4299 \ kg*m^2/s^2[/tex]

[tex]PE= 40.4299 \ J[/tex]

The textbook has 40.4299 Joules of potential energy.

Answer:

Distance

Explanation:

There as you see the lines are in a following of a path, like marathon. IT also states above each structure. Start and finish, why would it show motion. It shows distance.

Answer:

See Explanation

Explanation:

Let us consider the ionization of these compounds;

H3PO4 ⇔3H^+ + PO4^3-

H3BO3  ⇔3H^+ + BO3^3-

The next to consider is the type of electrolyte the both solution are; the both solutions are weak electrolytes and weak electrolytes do not ionize to a large extent.

The implication of this is that, not so much number of ions is added to the solution due to the poor ionization of these weak electrolytes. Hence, in spite of the subscript of 3, the conductivity of the solution does not significantly improve for the reason stated here quite unlike when strong electrolytes are used.

Answer:

the heavy one

Explanation:

the heavy one because heavy things and break things and the light one can't

Explanation:

The right answer is C

Hope i could be helpful