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3 years ago

To make an observation we need to record ______ information.

Chemistry

1 answer:

kkurt [141]3 years ago

6 0

All of the above. When making observations, we should try to incorporate as many senses as possible.

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Cuales elementos tienen solo un electrón de valencia

aleksley [76]

Answer:

En el caso del sodio, la valencia es 1, ya que tiene un solo electrón de valencia, si pierde un electrón se queda con el último nivel completo.

Explanation:

Grupo de la tabla periódica Electrones de valencia

Grupo 14 (IV) (Grupo del carbono) 4

Grupo 15 (V) (Grupo del nitrógeno ) 5

6 0

3 years ago

After a hypothesis is tested a scientist must do what next ?

zubka84 [21]

Test the hypothesis in an expirement!

3 0

3 years ago

An air bubble with a radius of 2.5 cm at the bottom of a lake where the temperature is 5.4 0C and the pressure is 3.2atm rises t

olasank [31]

Answer:

3.8 cm

Explanation:

Given data

Initial pressure (P₁): 3.2 atm

Initial volume (V₁): 65 cm³

Volume of a sphere: V = 4/3 × π × r³ = 4/3 × π × (2.5 cm)³ = 65 cm³

Initial temperature (T₁): 5.4°C + 273.15 = 278.6 K

Final pressure (P₂): 1.0 atm

Final volume (V₂): ?

Final temperature (T₂): 25.0°C + 273.15 = 298.2 K

We can find the final volume using the combined gas law.

$\frac{P_{1}\times V_{1}}{T_{1}} =\frac{P_{2}\times V_{2}}{T_{2}}\\\frac{3.2atm\times 65cm^{3} }{278.6K} =\frac{1.0atm\times V_{2}}{298.2K}\\V_{2}=223cm^{3}$

The final radius of the bubble is:

V = 4/3 × π × r³

223 cm³ = 4/3 × π × r³

r = 3.8 cm

6 0

4 years ago

How can you use graphs to calculate the displacement of an object?

Gala2k [10]

The area covered by a velocity-time graph

Explanation:

One important graphical method to the solution of displacement of an object is find the area covered by the curve. Displacement is the distance covered by a body during a particular period in time.

A velocity-time graph has velocity on the vertical axis and time on the horizontal axis.
With acceleration, the curve takes shapes and changes. There are periods of no acceleration,constant velocity, deceleration often observed on a velocity-time graph.
Using this, one can determine the displacement of an object looking for the area of the shape the curve covers.

Learn more:

brainly.com/question/568302

brainly.com/question/11220787

#learnwithBrainly

4 0

3 years ago

Calculate Δ H° for the reaction C 4H 4( g) + 2H 2( g) → C 4H 8( g), using the following data: Δ H° combustion for C 4H 4( g) = –

arlik [135]

<u>Answer:</u> The enthalpy of the reaction is coming out to be 2231 kJ.

<u>Explanation:</u>

Enthalpy change is defined as the difference in enthalpies of all the product and the reactants each multiplied with their respective number of moles. It is represented as $\Delta H^o$

The equation used to calculate enthalpy change is of a reaction is:

$\Delta H^o_{rxn}=\sum [n\times \Delta H^o_{(product)}]-\sum [n\times \Delta H^o_{(reactant)}]$

For the given chemical reaction:

$C_4H_4(g)+2H_2(g)\rightarrow C_4H_8(g)$

The equation for the enthalpy change of the above reaction is:

$\Delta H^o_{rxn}=[(1\times \Delta H^o_{(C_4H_8(g))})]-[(1\times \Delta H^o_{(C_4H_4(g))})+(2\times \Delta H^o_{(H_2(g))})]$

We are given:

$\Delta H^o_{(C_4H_8(g))}=-2755kJ/mol\\\Delta H^o_{(H_2(g))}=-286kJ/mol\\\Delta H^o_{(C_4H_4(g))}=-2341kJ/mol$

Putting values in above equation, we get:

$\Delta H^o_{rxn}=[(1\times (-2755))]-[(1\times (-286))+(2\times (-2341))]\\\\\Delta H^o_{rxn}=2213kJ$

Hence, the enthalpy of the reaction is coming out to be 2231 kJ.

5 0

3 years ago