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3 years ago

PLEASE HELP ASAP WILL MARK BRAINLIEST

2 answers:

8 0

It atomic number is 78, and the element is Platinum (Pt)
Its atomic mass is 195.078

hope this helps please mark brainliest

goldenfox [79]3 years ago

4 0

Keep in mind that atomic number is the number of protons in the atom of the element. Therefore, in the case where there are 78 protons, we can conclude that the atomic number of this element is ALSO 78.

Let me know if you need anything else.

- Dotz

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If 8.500 g CH is burned and the heat produced from the burning is added to 5691 g of water at 21 °C, what is the final

mojhsa [17]

The final temperature = 36 °C

<h3>Further explanation</h3>

The balanced combustion reaction for C₆H₆

2C₆H₆(l)+15O₂(g)⇒ 12CO₂(g)+6H₂O(l) +6542 kJ

MW C₆H₆ : 78.11 g/mol

mol C₆H₆ :

$\tt \dfrac{8.5}{78.11}=0.109$

Heat released for 2 mol C₆H₆ =6542 kJ, so for 1 mol

$\tt \dfrac{0.109}{2}\times 6542=356.539~kJ/mol$

Heat transferred to water :

Q=m.c.ΔT

$\tt 356.539=5.691~kg\times 4.18~kj/kg^oC\times (t_2-21)\\\\t_2-21=15\rightarrow t_2=36^oC$

3 0

2 years ago

Write down the molecular formula and molecular weight of carbon dioxide .

Finger [1]

Answer:

CO2

Molar mass: 44.01 g/mol

Explanation:

CO2

3 0

3 years ago

german

Order of metals from least reactive to most reactive: B <C <A <D

<h3>Further explanation</h3>

Reducing agents are substances that experience oxidation

Oxidizing agents are substances that experience reduction

The metal activity series is expressed in voltaic series

The more to the left, the metal is more reactive (easily release electrons) and the stronger reducing agent

The more to the right, the metal is less reactive (harder to release electrons) and the stronger oxidizing agent

So that the metal located on the left can push the metal on the right in the redox reaction

Let's analyze the statement in the problem

I. Only A, C and D react with 1 mol/L HCl to give H₂(e)

M + HCl ⇒ MCl + H₂(MCl : alkali, MCl₂ : alkaline earth)

A, C and D can react with 1 mol / L HCl, meaning metals A, C and D are located to the left of element H (more reactive), and B in the right of element H

II. When A is added to solutions of the other metal ions, metallic B and C are formed but not D.

This means that metal A is more reactive than metals B and C, while D is more reactive than A, so metal D is the most reactive

3 0

2 years ago

Considering the temperature vs. time graph below, how does the temperature at the beginning of a change of state

Cloud [144]

Answer:

The temperature is always lower.

Explanation:

The temperature is always lower at the end of the state as compared to beginning of the state. We can see in the given data, the temperature is higher at the beginning i. e. 140 degree Celsius but with the passage of time, the temperature of a state decreases constantly and the temperature at the end is lower i. e. 20 degree Celsius. So we can conclude that the temperature is always lower.

6 0

3 years ago

Read 2 more answers

rutherford's experiment indicated that matter was not as uniform as it appears what part of his experimental results implied thi

MaRussiya [10]

Rutherford theorized that atoms have their charge concentrated in a very small nucleus.

This was famous Rutherford's Gold Foil Experiment: he bombarded thin foil of gold with positive alpha particles (helium atom particles, consist of two protons and two neutrons).

Rutherford observed the deflection of alpha particles on the photographic film and notice that most of alpha particles passed straight through foil.

That is different from Plum Pudding model, because it shows that most of the atom is empty space.

According to Rutherford model of the atom:

1) Atoms have their charge concentrated in a very small nucleus.

2) Major space in an atom is empty.

3) Atoms nucleus is surrounded by negatively charged particles called electrons.

4) An atom is electrically neutral.

6 0

3 years ago