Ask question

Ask question

All categories

3 years ago

11

How would I find the number of protons, neutrons and electrons when I only have the atomic number and atom (assignment says assu

me the net charge is 0)

1 answer:

coldgirl [10]3 years ago

8 0

Explanation:

Atomic number , protons and electrons have the same value / their value is same .

But for the neutron there is no specific technique. You have to remember the neutrons of every element

You might be interested in

1, 2 and 3 ........

Orlov [11]

2.) Average atomic mass =Σ (abundance x molar mass) /100 = (12.64 x 302.04 + 18.23 x 304.12 + 69.13 x 305.03) /100 =304.486 u(Dalton) . This is avg atomic mass.

8 0

4 years ago

A biology student set up an experiment to study 9 mice. On day 1, they were measured for weight and length. Then the mice were p

Sophie [7]

The independent variable would be the variable in the research that is being manipulated by the researcher. In this case, it would be temperature in the cage as it is what is being manipulated and changed in the research design. The dependent variable would be the variable that is being studied so, for this case, it would be the length and the weight of the mice. The constants are the factors that might affect the dependent variable but is held constant or the same by the researcher throughout the experiment. These are the size of the cage, amount of food and the exercise wheel. The flaw that the scientist would be studying the length of the mice since I don't think the temperature has any effect on it. And base from he results, the change in lengths are not conclusive.

4 0

3 years ago

Which of the following lists of elements are in the same PERIOD? *

yuradex [85]

Ca, V, Cu, Kr
Remember a period is a the horizontal rows in the Periodic Table.

5 0

3 years ago

Which statement best describes the way a catalyst works?

bogdanovich [222]

Answer: E. It decreases the value of Eact.

Explanation:

Activation energy is the extra energy that must be supplied to reactants in order to cross the energy barrier and thus convert to products.

A catalyst is a substance which increases the rate of a reaction by taking the reaction through a different path which involves lower activation energy and thus more molecules can cross the energy barrier and more molecules convert to products.

The catalyst itself does not take part in the chemical reaction and is regenerated as such at the end.

6 0

3 years ago

Consider the dissolution of 2.50 grams of salt XY in 75.0 mL of water within a calorimeter. The temperature of the water decreas

mel-nik [20]

Answer : The enthalpy change for dissolving this salt on a energy per mass basis is 132.4 J/g

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 = $42.2J/^oC$

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

$m_2$ = mass of water = $Density\times Volume=1/mL\times 75.0mL=75.0g$

$\Delta T$ = change in temperature = $0.93^oC$

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

$q=[(42.2J/^oC\times 0.93^oC)+(75.0g\times 4.184J/g^oC\times 0.93^oC)]$

$q=331.08J$

Now we have to calculate the enthalpy change for dissolving this salt on a energy per mass basis.

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

where,

$\Delta H$ = enthalpy change = ?

q = heat released = 331.08 J

m = mass of salt = 2.50 g

$\Delta H=\frac{331.08J}{2.50g}=132.4J/g$

Therefore, the enthalpy change for dissolving this salt on a energy per mass basis is 132.4 J/g

5 0

3 years ago