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2 years ago

An atom has 25 protons,20 neutrons, and 19 electrons.Which atom is this,What is the atom's mass number?

Chemistry

2 answers:

ladessa [460]2 years ago

6 0

The atomic mass is 45

Arte-miy333 [17]2 years ago

3 0

The atom is manganese

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If 45.0 mL of ethanol (density =0.789g/mol) initially at 6.0°C mix with 45.0 mL of water (density =1.0 g/mol) initially at 28.0°

Likurg_2 [28]

The final temperature of the mixture : 21.1° C

<h3>Further explanation </h3>

The law of conservation of energy can be applied to heat changes, i.e. the heat received / absorbed is the same as the heat released

Q in(gained) = Q out(lost)

Heat can be calculated using the formula:

Q = mc∆T

Q = heat, J

m = mass, g

c = specific heat, joules / g ° C

∆T = temperature difference, ° C / K

Q ethanol=Q water

mass ethanol=

$\tt mass=\rho\times V\\\\mass=0.789\times 45=35.505~g$

mass water =

$\tt mass=1~g/ml\times 45~ml=45~g$

then the heat transfer :

$\tt 35.505\times 2.42~J/g^oC\times (t-6)=45\times 4.18~J/g^oC\times (28-t)\\\\85.922t-515.533=5266.8-188.1t\\\\274.022t=5782.33\rightarrow t=21.1^oC$

5 0

2 years ago

A train in Japan can travel 813.5 miles in 5 hours

Anastaziya [24]

Answer:

162.7miles/hr

Explanation:

Given parameters:

Distance covered by the train = 813.5miles

Time taken = 5hours

Unknown:

Speed of the train = ?

Solution:

Speed is a physical quantity.

It is mathematically expressed as;

Speed = $\frac{distance}{time}$

So, input parameters and solve;

Speed = $\frac{813.5}{5}$ = 162.7miles/hr

8 0

2 years ago

Help please its science

Nookie1986 [14]

Answer: any answer choices

Explanation:

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2 years ago

The specific heat of aluminum is s 9.00 J/g C how much energy is needed to raise the temperature of 20.0 g block of aluminum fro

Nimfa-mama [501]

E=MC(delta)T
=20.0g x 9.00J/g x (94.4-22.8) C
= 12,924.0 J

7 0

2 years ago

Elements join together to form_____.

sineoko [7]

Answer:

compounds

Explanation:

6 0

2 years ago