Write the empirical formula for 3.57 g of N and 4.08 g of O. Express answer as a chemical formula.

How does a sample of water at 38 °C compare to a sample of water at 295 K? The water at 38 °C has a lower average kinetic energy

Drupady [299]

Answer:

The water at 38 °C has faster-moving molecules than the sample at 295 K.

Explanation:

Converting the temperature, 295 K from Kelvin to Celsius:

295 - 273 = 22°C

⇒The boiling point of water is 100°C and its melting point 0°C

⇒When we compare water at those 2 different temperatures ( 22°C and 38°C) we can say that water is in liquid form at both these temperatures as both of them are quite below the boiling temperature and above the melting temperature.

⇒The difference in temperature between water at the 2 given temperatures = 38°C - 22°C = 16°C

Water at 38°C is at a higher temperature and so is warmer than water at a lower temperature of 22°C.

At the atomic scale, the kinetic energy of atoms and molecules is sometimes referred to as heat energy. Kinetic energy is also related to the concept of temperature. Temperature is defined as the measure of the average speed of atoms and molecules. The higher the temperature, the faster these particles of matter move.

3 0

3 years ago

Find the enthalpy of neutralization of HCl and NaOH. 87 cm3 of 1.6 mol dm-3 hydrochloric acid was neutralized by 87 cm3 of 1.6 m

Vesna [10]

Answer : The correct option is, (A) -101.37 KJ

Explanation :

First we have to calculate the moles of HCl and NaOH.

$\text{Moles of HCl}=\text{Concentration of HCl}\times \text{Volume of solution}=1.6mole/L\times 0.087L=0.1392mole$

$\text{Moles of NaOH}=\text{Concentration of NaOH}\times \text{Volume of solution}=1.6mole/L\times 0.087L=0.1392mole$

The balanced chemical reaction will be,

$HCl+NaOH\rightarrow NaCl+H_2O$

From the balanced reaction we conclude that,

As, 1 mole of HCl neutralizes by 1 mole of NaOH

So, 0.1392 mole of HCl neutralizes by 0.1392 mole of NaOH

Thus, the number of neutralized moles = 0.1392 mole

Now we have to calculate the mass of water.

As we know that the density of water is 1 g/ml. So, the mass of water will be:

The volume of water = $87ml+87ml=174ml$

$\text{Mass of water}=\text{Density of water}\times \text{Volume of water}=1g/ml\times 174ml=174g$

Now we have to calculate the heat absorbed during the reaction.

$q=m\times c\times (T_{final}-T_{initial})$

where,

q = heat absorbed = ?

$c$ = specific heat of water = $4.18J/g^oC$

m = mass of water = 174 g

$T_{final}$ = final temperature of water = 317.4 K

$T_{initial}$ = initial temperature of metal = 298 K

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

$q=174g\times 4.18J/g^oC\times (317.4-298)K$

$q=14110.008J=14.11KJ$

Thus, the heat released during the neutralization = -14.11 KJ

Now we have to calculate the enthalpy of neutralization.

$\Delta H=\frac{q}{n}$

where,

$\Delta H$ = enthalpy of neutralization = ?

q = heat released = -14.11 KJ

n = number of moles used in neutralization = 0.1392 mole

$\Delta H=\frac{-14.11KJ}{0.1392mole}=-101.37KJ/mole$

Therefore, the enthalpy of neutralization is, -101.37 KJ

3 0

3 years ago

When polonium-210 emits an alpha particle, the child isotope has an atomic mass of

Sergeeva-Olga [200]

Answer: The child isotope has an atomic mass of 206.

Explanation:

Alpha decay : When a larger nuclei decays into smaller nuclei by releasing alpha particle. In this process, the mass number and atomic number is reduced by 4 and 2 units respectively.

General representation of an element is given as: $_Z^A\textrm{X}$

where,

Z represents Atomic number

A represents Mass number

X represents the symbol of an element

General representation of alpha decay :

$_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}Y+_2^4\alpha$

$_{84}^{210}\textrm{Po}\rightarrow_{82}^{206}\textrm{Pb}+_2^4\textrm{He}$

8 0

3 years ago

Read 2 more answers

Is the normal resting position of an object.

NemiM [27]

Answer:

being stationary relative to a particular frame of reference or another object; when the position of a body with respect to its surroundings does not change with time it is said to be at rest

Explanation:

4 0

3 years ago

Sitting at a four-legged table there is: 1 grandma, 2 moms, 2 daughters and a granddaughter. How many legs are under the table?

lbvjy [14]

Answer:

The answer is 14 "legs"

Explanation:

There are 2 legs per person so 10 legs (5 people * 2) plus the 4 legs the table has.

3 0

3 years ago