Who were the terrorists that attacked the united states on September 11, 2001

An atom's Lewis dot structure has four dots. Which of the following elements could it be, and why?

Elis [28]

Answer:

Beryllium, because it is in period 2 and has four total electrons.

Explanation:

7 0

3 years ago

How long is a red blood cell

Lera25 [3.4K]

I suspect this question should read "How long does a red blood cell live." A red blood cell lives for between 100 and 120 days. It takes 7 days for a new red blood cell to develop from stem cells. Stem cells are similar to base cells. They can also be seen as a general template from which specialized cells are made. Stem cells can be taken from a newborn baby's umbilical chord or extracted from an adult blood donor's blood.This

7 0

2 years ago

Could someone help me balance this chemical equation please

Softa [21]

Balanced equation:
Ca(OH)2+H2SO4=CaSO4+2 H20<span />

4 0

2 years ago

A 50.0 mL sample of a 1.00 M solution of CuSO4 is mixed with 50.0 mL of 2.00 M KOH in a calorimeter. The temperature of both sol

Reika [66]

Answer : The enthalpy change for the process is 52.5 kJ/mole.

Explanation :

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

$q=[q_1+q_2]$

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

where,

q = heat released by the reaction

$q_1$ = heat absorbed by the calorimeter

$q_2$ = heat absorbed by the solution

$c_1$ = specific heat of calorimeter = $12.1J/^oC$

$c_2$ = specific heat of water = $4.18J/g^oC$

$m_2$ = mass of water or solution = $Density\times Volume=1/mL\times 100.0mL=100.0g$

$\Delta T$ = change in temperature = $T_2-T_1=(26.3-20.2)^oC=6.1^oC$

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

$q=[(12.1J/^oC\times 6.1^oC)+(100.0g\times 4.18J/g^oC\times 6.1^oC)]$

$q=2623.61J$

Now we have to calculate the enthalpy change for the process.

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

where,

$\Delta H$ = enthalpy change = ?

q = heat released = 2626.61 J

n = number of moles of copper sulfate used = $Concentration\times Volume=1M\times 0.050L=0.050mole$

$\Delta H=\frac{2623.61J}{0.050mole}=52472.2J/mole=52.5kJ/mole$

Therefore, the enthalpy change for the process is 52.5 kJ/mole.

8 0

3 years ago

An atom has 24 protons and 23 electrons and 28 neutrons what charge does this atom have?

alina1380 [7]

Answer:

1+

Explanation:

the number of protons tells you which element it is in the periodic table, you can notice that there is 1 less electron that then there is protons which means that the element had to give 1 electron away. When you get rid of 1 e- you have 1 proton more that electrons so that's why it's 1+

also the element is Cr

3 0

3 years ago