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2 years ago

What is chemical change? what are some ways to tell chemical change happened?

Chemistry

1 answer:

andrew-mc [135]2 years ago

4 0

Answer:

A chemical change occurs when the reactants chemical compositions have changed

Explanation:

a change in colour, change in temperature, change in smell, formation of a precipitate, or the formation of gas bubbles

Hopes this helps

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2. What group is Ballardium located? (Bu) *

elena-14-01-66 [18.8K]

Answer:

This question appears incomplete

Explanation:

There is no such element known as "Ballardium (Bu)" in the periodic table. However, there are elements with a bit of similarity in spellings and pronunciation such as Beryllium (Be) which is found in group 2 (meaning it is an alkali earth metal), Berkelium (Bk) which is an actinide (meaning it is radioactive) and Vanadium (V) which is found in group 5 of the periodic table (meaning it's a transition metal).

5 0

2 years ago

Calculate the enthalpy of the reaction

harkovskaia [24]

Answer : The enthalpy of the reaction is, -2552 kJ/mole

Explanation :

According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.

According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.

The given enthalpy of reaction is,

$4B(s)+3O_2(g)\rightarrow 2B_2O_3(s)$ $\Delta H=?$

The intermediate balanced chemical reactions are:

(1) $B_2O_3(s)+3H_2O(g)\rightarrow 3O_2(g)+B_2H_6(g)$ $\Delta H_A=+2035kJ$

(2) $2B(s)+3H_2(g)\rightarrow B_2H_6(g)$ $\Delta H_B=+36kJ$

(3) $H_2(g)+\frac{1}{2}O_2(g)\rightarrow H_2O(l)$ $\Delta H_C=-285kJ$

(4) $H_2O(l)\rightarrow H_2O(g)$ $\Delta H_D=+44kJ$

Now we have to revere the reactions 1 and multiple by 2, revere the reactions 3, 4 and multiple by 2 and multiply the reaction 2 by 2 and then adding all the equations, we get :

(when we are reversing the reaction then the sign of the enthalpy change will be change.)

The expression for enthalpy of the reaction will be,

$\Delta H=-2\times \Delta H_A+2\times \Delta H_B-6\times \Delta H_C-6\times \Delta H_D$

$\Delta H=-2(+2035kJ)+2(+36kJ)-6(-285kJ)-6(+44)$

$\Delta H=-2552kJ$

Therefore, the enthalpy of the reaction is, -2552 kJ/mole

4 0

3 years ago

Temperature in degrees Fahrenheit can be converted to Celsius by first subtracting 32, then dividing by 1.8. What is the Celsius

kap26 [50]

Answer:

31.1°C

Explanation:

Given parameters:

Temperature = 88°F

The formula of the to convert is:

T°F = T°C - 32 / 1.8 = $\frac{TC - 32}{1.8}$

Now input the parameters and solve;

T°F = $\frac{ 88 -32}{1.8}$

T°F = 31.1°C

7 0

2 years ago

Read 2 more answers

What would happen if uranium-241 lost 2 protons and 2 neutrons?

kupik [55]

If uranium-241 lost 2 protons and 2 neutrons, then thorium-237 would be produced. The number beside the element is the mass number which is the sum of protons and neutrons. If uranium would lose 2 protons and 2 neutrons, then the mass number would decrease by 4 making it 237. Looking in a periodic table, thorium is the element which has a mass number of 237.

5 0

3 years ago

What would happen if the

AleksAgata [21]

Either everything would solid (strong attractive force), liquid or gas (weaker attractive force). Everything would be the same matter

7 0

3 years ago