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konstantin123 [22]
3 years ago
9

How many protons are in the nucleus of this atom? What is the mass number of this atom?

Chemistry
1 answer:
Anettt [7]3 years ago
3 0
Ummmmmmmmmmmmmmmmmmmmmmmmm, 21

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When 1.04g of cyclopropane was burnt in excess oxygen in a bomb calorimeter, the temperature rose by 3.69K. The total heat capac
STatiana [176]

Answer:

\Delta _{comb}H=-2,093\frac{kJ}{mol}

Explanation:

Hello!

In this case, since these calorimetry problems are characterized by the fact that the calorimeter absorbs the heat released by the combustion of the substance, we can write:

Q_{rxn}+Q_{cal}=0

Thus, given the temperature change and the total heat capacity, we obtain the following total heat of reaction:

Q_{rxn}=-14.01kJ/K*3.69K\\\\Q_{rxn}=-51.70kJ

Now, by dividing by the moles in 1.04 g of cyclopropane (42.09 g/mol) we obtain the enthalpy of combustion of this fuel:

n=\frac{1.04g}{42.09g/mol}=0.0247mol\\\\\Delta _{comb}H=\frac{Q_{rxn}}{n}\\\\  \Delta _{comb}H=-2,093\frac{kJ}{mol}

Best regards!

4 0
3 years ago
How many atoms and ions does nickel oxide have?
Alex73 [517]

Answer: 1 atom

Explanation:

The loss of the remaining valence electron results in an ion with a +2 charge. The proper way of noting the charges on these ions is to use the systematic name for each ion, nickel (I) for the +1 ion and nickel (II) for the +2 ion.

4 0
3 years ago
What is the main cause of any change of state?
svetoff [14.1K]

Answer:

Adding or removing energy from matter causes a physical change as matter moves from one state to another. For example, adding thermal energy (heat) to liquid water causes it to become steam or vapor (a gas). And removing energy from liquid water causes it to become ice (a solid).

6 0
3 years ago
Read 2 more answers
1. A student tried to solve the following problem by selecting the tile as shown. What, if anything, did the student do wrong?
slega [8]

Answer:

B. The student chose the correct tile, but needs to flip the tile to make the units cancel

Explanation:

Based on the reaction:

2AgNO₃(aq) + Cu(s) → 2Ag(s) + Cu(NO₃)₂ (aq)

<em>2 moles of AgNO₃ react per mole of Cu producing 2 moles of Ag and 1 mole of Cu(NO₃)₂</em>

Thus, if you want to produce 6.75moles of Cu(NO₃)₂ you need:

6.75moles of Cu(NO_3)_2  \frac{2 mol AgNO_3 }{1 mol Cu(NO_3)_2} = 13.50 moles of AgNO₃ are needed

Thus, if you analize the tile shown by the student:

<em>B. The student chose the correct tile, but needs to flip the tile to make the units cancel</em>

6 0
3 years ago
How would u describe the cells that make up the parts of your eye?​
aleksandrvk [35]

Answer:

optical (optic is the word used for referring to the eye ie optic nerve)

Explanation:

4 0
3 years ago
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