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Mazyrski [523]
2 years ago
14

Theses are the questions please help

Chemistry
1 answer:
leva [86]2 years ago
6 0
Remember that as we move from left to right we increase an electron and a proton both by 1.
Like when we go from A to B we will add one proton and one electron.

Also, when we down from top to bottom in same column of the periodic table then the number of electrons do not change.

ANSWERS

1) 5.

2) 7.

3) 4

4) 14

5) 3
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Give two possible reasons why using tap water instead of distilled water could give misleading
hodyreva [135]

Answer:

Explanation:

Public tap water is not desirable when carrying out experiments in the laboratory.

The chemical definition of water is a compound made up of two atoms of hydrogen to 1 atom of oxygen. Any violation simply desist from the true meaning of water.

Why are tap water not used:

  • They contain other dissolved ions like chlorine which have been added in their treatment. This alters the fundamental molecules that is expected to be seen in water. Water of this nature can affect experimental results seriously.
  • Tap water can become a mixture instead of a simple compound. A mixture is a combination of several compounds. Such water will have a varied composition and make simplification of experiments very difficult.
7 0
3 years ago
A gas sample occupies a volume of 1.264 L when the temperature is 168.0 °C and the pressure is 946.6 torr. How many molecules ar
alukav5142 [94]

Answer:

0.26×10²³ molecules

Explanation:

Given data:

Volume of gas = 1.264 L

Temperature = 168°C

Pressure = 946.6 torr

Number of molecules of gas = ?

Solution:

Temperature = 168°C (168+273= 441 K)

Pressure = 946.6 torr (946.6/760 = 1.25 atm)

Now we will determine the number of moles.

PV = nRT

P= Pressure

V = volume

n = number of moles

R = general gas constant = 0.0821 atm.L/ mol.K  

T = temperature in kelvin

n = PV/RT

n = 1.25  atm ×1.264 L / 0.0821 atm.L/ mol.K   ×441 K

n = 1.58 /36.21 /mol

n = 0.044 mol

Now we will calculate the number of molecules by using Avogadro number.

1 mol = 6.022×10²³ molecules

0.044 mol × 6.022×10²³ molecules/ 1mol

0.26×10²³ molecules

5 0
2 years ago
We dissolve 93 grams of sodium sulfate (Na2SO4) in 20 grams of water. What is the percent by mass of sodium sulfate in this solu
dlinn [17]
It should be for the total solution of 93 plus 20 grams which is 113 grams so 93 divided by 113 grams comes to 82.3% sodium sulfate and this can be checked by multiplying 113 grams by 0.823 which results in 93 grams of sodium sulphate. 
4 0
3 years ago
If the container is closed and the ethanol is allowed to reach equilibrium with its vapor, how many grams of liquid ethanol rema
SVETLANKA909090 [29]

Explanation:

Let us assume that the given data is as follows.

        V = 3.10 L,        T = 19^{o}C = (19 + 273)K = 292 K

       P = 40 torr    (1 atm = 760 torr)

So,     P = \frac{40 torr}{760 torr} \times 1 atm

             = 0.053 atm

          n = ?

According to the ideal gas equation, PV = nRT.

Putting the given values into the above equation to calculate the value of n as follows.

                 PV = nRT

   0.053 atm \times 3.10 L = n \times 0.0821 L atm/mol K \times 292 K

                 0.1643 = n \times 23.97

                    n = 6.85 \times 10^{-3}

It is known that molar mass of ethanol is 46 g/mol. Hence, calculate its mass as follows.

               No. of moles = \frac{mass}{\text{molar mass}}

                 6.85 \times 10^{-3} = \frac{mass}{46 g/mol}  

                    mass = 315.1 \times 10^{-3} g

                              = 0.315 g

Thus, we can conclude that the mass of liquid ethanol is 0.315 g.

4 0
3 years ago
What is one example of boyles law
damaskus [11]
One of the examples of Boyles law in action is a syringe 




3 0
3 years ago
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