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2 years ago

What is the length of the pencil in cm?

Chemistry

1 answer:

Levart [38]2 years ago

7 0

Answer:

16 cm

Explanation:

Because when you look at the ruler, it shows the length as 16 cm

You might be interested in

How did Mendeleev arrange the known elements?

Agata [3.3K]

In order of relative atomic mass.

4 0

3 years ago

Read 2 more answers

A bomb calorimeter has a heat capacity of 783 J/oC and contains 254 g of water whose specific heat capacity is 4.184 J/goC. How

IrinaK [193]

Answer : The amount of heat evolved by a reaction is, 4.81 kJ

Explanation :

Heat released by the reaction = Heat absorbed by the calorimeter + Heat absorbed by the water

$q=[q_1+q_2]$

$q=[c_1\times \Delta T+m_2\times c_2\times \Delta T]$

where,

q = heat released by the reaction

$q_1$ = heat absorbed by the calorimeter

$q_2$ = heat absorbed by the water

$c_1$ = specific heat of calorimeter = $783J/^oC$

$c_2$ = specific heat of water = $4.184J/g^oC$

$m_2$ = mass of water = 254 g

$\Delta T$ = change in temperature = $T_2-T_1=(23.73-26.01)=-2.28^oC$

Now put all the given values in the above formula, we get:

$q=[(783J/^oC\times -2.28^oC)+(254g\times 4.184J/g^oC\times -2.28^oC)]$

$q=-4208.28J=-4.81kJ$

Therefore, the amount of heat evolved by a reaction is, 4.81 kJ

7 0

3 years ago

13. A gas occupies 4.31 liters at a pressure of 0.755 atm. Determine the volume if the

wariber [46]

Answer:

13. 2.60 L.

14. 2.40 L.

Explanation:

We can use the general law of ideal gas: PV = nRT.

where, P is the pressure of the gas in atm.

V is the volume of the gas in L.

n is the no. of moles of the gas in mol.

R is the general gas constant,

T is the temperature of the gas in K.

If n and T are constant, and have different values of P and V:

(P₁V₁) = (P₂V₂)

<em>13. A gas occupies 4.31 liters at a pressure of 0.755 atm. Determine the volume if the pressure is increased to 1.25 atm.</em>

P₁ = 0.755 atm, V₁ = 4.31 L.

P₂= 1.25 atm, V₂ = ??? L.

∴ V₂ = (P₁V₁)/(P₂) = (0.755 atm)(4.31 L)/(1.25 atm) = 2.60 L.

<em>14. 600.0 mL of a gas is at a pressure of 8.00 atm. What is the volume of the gas at 2.00 at m.</em>

P₁ = 8.0 atm, V₁ = 600.0 mL.

P₂= 2.0 atm, V₂ = ??? L.

∴ V₂ = (P₁V₁)/(P₂) = (8.0 atm)(600.0 mL)/(2.0 atm) = 2400/0 mL = 2.40 L.

3 0

2 years ago

As you move from bottom on the periodic table to the top shielding

masha68 [24]

Answer:

AS we move from bottom to top on periodic table shielding decreased.

Explanation:

As we move from left to right across the periodic table the number of valance electrons in an atom increase. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons. This effect lead to the greater nuclear attraction.

As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased.

As we move from bottom to top the energy level decreased because of decreased in electron thus shielding decreased and atomic size also decreased.

3 0

3 years ago

0.28gram of NH3 on decomposition gave 0.25gram of nitrogen and hydrogen. Find the volume of hydrogen evolved at Ntp. (2gram hydr

hodyreva [135]

The volume of H₂ evolved at NTP=0.336 L

<h3>Further explanation</h3>

Reaction

Decomposition of NH₃

2NH₃ ⇒ N₂ + 3H₂

conservation mass : mass reactants=mass product

0.28 NH₃= 0.25 N₂ + 0.03 H₂

2 g H₂ = 22.4 L

so for 0.03 g :

$\tt \dfrac{0.03}{2}\times 22.4=0.336$

7 0

2 years ago