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I am Lyosha [343]
2 years ago
5

Please help chemistry timed test

Chemistry
2 answers:
Artist 52 [7]2 years ago
8 0

Answer:

Barrium nucleus has 56 protons and 137−56=81 neutrons.

Atomic Mass 137.327 atomic mass units

Number of Protons 56

Number of Neutrons 81

Number of Electrons 56

lakkis [162]2 years ago
7 0

Answer:

54

Barium atomic number is 56, this means that it has 56 protons in its nucleus and put it as a period 6 element. an uncharged barium atom would have 56 electron also. However as a group 2 element barium easily loses 2 electron to form the +2 cation. the ions has 56-2=54

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Nikolas, the fire extinguisher, and the skateboard have a combined mass of 50 kg. What force would the fire extinguisher have to
murzikaleks [220]

Answer:

Force used by fire extinguisher = 60 N

Explanation:

Given:

Mass of skateboard with fire extinguisher = 50 kg

Acceleration of fire extinguisher = 1.2 m/s²

Find:

Force used by fire extinguisher = ?

Computation:

⇒ Force = Mass × Acceleration

⇒ Force used by fire extinguisher = Mass of skateboard with fire extinguisher × Acceleration of fire extinguisher

⇒ Force used by fire extinguisher = 50 kg × 1.2 m/s²

⇒ Force used by fire extinguisher = 60 N

3 0
3 years ago
Read 2 more answers
What is the mass of CO2 lost at 20 min from the limestone sample?
harkovskaia [24]

Answer:

The mass, CO2 and CO3 from the limestone sample is discussed below in details.

Explanation:

(A) mass loss of sample of limestone after 20 min

= 0.8437g-0.5979g = 0.2458 g

From the given reaction of limestone, 2 mol of the sample gives 2 moles of CO 2.

Therefore  

184.4 g ( molar mass of limestone) gives2× 44 g of carbon dioxide.

1 g of sample gives 88/184.4 g of carbon dioxide

Hence 0.2458 g sample gives

= 88/184.4 × 0.2458 g = 0.117 g carbon dioxide

(B) mole of CO 2 lost = weight/ molar mass

= 0.117 g / 44 g/mol =0.0027 mole

(C). 1 mol of limestone contain 2 mol of carbonate ion

From the reaction we know that carbonate ion of limestone is converted into carbondioxide

Hence lost carbonate ion = 0.2458 g

(D) we know that

1 mol limestone contain 1mol CaCO​​​ 3

Hence in sample present CaCO​​​ 3

= 1mole / 184.4 g × 0.8437 g= 0.00458 mol CaCO​​​3

8 0
3 years ago
1. Which of the following is a correctly written thermochemical equation?
WITCHER [35]

Explanation:

1. Thermochemical equation is balance stoichiometric chemical equation written with the phases of the reactants and products in the brackets along with the enthalpy change of the reaction.

The given correct thermochemical reactions are:

Fe(s)+O_2(g)\rightarrow Fe_2O_3(s),\Delta H = 3,926 kJ


C_3H_8(g)+5O_2 (g)\rightarrow 3CO_2 (g)+4H_2O(l),\Delta H= 2,220 kJ/mol

2. Phase change affect the value of the enthalpy change of the thermochemical equation. This is because change in phase is accompanied by change in energy. For example:

H_2O(s)\rightarrow H_2O(g),\Delta H_{s}=51.1 kJ/mol

H_2O(l)\rightarrow H_2O(g),\Delta H_{v}=40.65 kJ/mol

In both reaction phase of water is changing with change in energy of enthalpy of reaction.

7 0
3 years ago
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Aleks04 [339]

Answer:

use vinager

Explanation:

I did this heh :/

7 0
3 years ago
I NEED HELP PLEASE! :)
MrMuchimi

<u>answer</u> 1<u> </u><u>:</u>

Law of conservation of momentum states that

For two or more bodies in an isolated system acting upon each other, their total momentum remains constant unless an external force is applied. Therefore, momentum can neither be created nor destroyed.

<u>answer</u><u> </u><u>2</u><u>:</u><u> </u>

When a substance is provided energy<u> </u>in the form of heat, it's temperature increases. The extent of temperature increase is determined by the heat capacity of the substance. The larger the heat capacity of a substance, the more energy is required to raise its temperature.

When a substance undergoes a FIRST ORDER phase change, its temperature remains constant as long as the phase change remains incomplete. When ice at -10 degrees C is heated, its temperature rises until it reaches 0 degrees C. At that temperature, it starts melting and solid water is converted to liquid water. During this time, all the heat energy provided to the system is USED UP in the process of converting solid to the liquid. Only when all the solid is converted, is the heat used to raise the temperature of the liquid.

This is what results in the flat part of the freezing/melting of condensation/boiling curve. In this flat region, the heat capacity of the substance is infinite. This is the famous "divergence" of the heat capacity during a first order phase transition.

There are certain phase transitions where the heat capacity does not become infinitely large, such as the process of a non-magnetic substance becoming a magnetic substance (when cooled below the so-called Curie temperature).

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