Answer:

Explanation:
We are asked to find how much heat a sample of copper absorbs when the temperature is increased.
Since we know the mass, temperature increase, and specific heat capacity, we can use the following formula to calculate heat.

The mass of the copper sample is 100 grams, the temperature is changed or increased by 30.0 degrees Celsius, and the specific heat of copper is 0.39 Joules per gram degrees Celsius.
- m= 100 g
- c= 0.39 J/g °C
- ΔT= 30.0 °C
Substitute the values into the formula.

Multiply the first two values. Note that the units of grams cancel.

Multiply again, this time the units of degrees Celsius cancel.

The copper sample absorbs <u>1170 Joules</u> of heat and <u>Choice B </u>is correct.
Answer: For every one mole of Ca used in this reaction, two mols of H20 are used, one mole of Ca(OH)2 is formed, and one mole of H2 is formed.
Explanation: Once the equation is balanced, you can get the ratio from the coefficients. If you are looking at the ratio of Ca to H2O, the ratio is 1:2; Ca to H2 1:1.
Answer: Objects with like charge repel each other.
Answer:
The main difference between the two models is <em>the position of the electron in the atom</em>.
Explanation:
- <em>Bohr model:</em> The electrons are moved around the nucleus in circular definite paths (orbitals or shells). Also, he could not find or detect the exact position of electron.
- <em>Electron cloud model:</em> It is supposed by Erwin Schrodinger. He showed that the emission spectra of the atom is the way to detect the probability of electron position.