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3 years ago

Calculate the average atomic mass for the element beryllium, given this information about the

Chemistry

2 answers:

Darya [45]3 years ago

5 0

Answer: 9.007

Explanation:

Be-8 8 x 0.20% = 0.016

Be-9 9 x 98.90% = 8.901

Be-10 10 x 0.90% = 0.09

100.00% 9.007

Vesna [10]3 years ago

3 0

Less Credit so, I won't able

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When converting an “ordinary” number that is greater than 1 to scientific notation, how many non-zero digits are to the LEFT of

oksian1 [2.3K]

Answer: 0 I think

Explanation:

pretty sure its zero because i learned it last year but im in middle school so you might want to look it up.

5 0

4 years ago

What mass of sodium hydroxide is needed to neutralise 24.5kg of sulfuric acid H2SO4 + N2 = 2NH3

sveticcg [70]

Answer:

23.92 g

Explanation:

Molar mass of H2SO4 = (2×1)+32+(16×4)= 2+32+48= 82g/mol

H2SO4 + 2NaOH ---> Na2SO4 + 2H2O

I mole of H2SO4 = 2 moles of NaOH

24.5/82 = 24.5/82 × 2

= 0.598 moles of NaOH will neutralize

Mass= mole× molar mass

Molar mass of NaOH= 23+16+1 = 40g/mol

Mass= 0.598 × 40 = 23.92g of NaOH

7 0

3 years ago

A sample of tin (Cp = 0. 227 J/gâ€˘Â°C) is placed in a freezer. Its temperature decreases from 15. 0Â°C to â’10. 0Â°C as it rele

pshichka [43]

Taking into account the definition of calorimetry, the mass of the sample is 478.41 grams.

Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.

Sensible heat is defined as the amount of heat that a body absorbs or releases without any changes in its physical state (phase change).

So, the equation that allows to calculate heat exchanges is:

Q = c× m× ΔT

where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.

In this case, you know:

Q= -543 J because the energy is releases
c= 0.227 $\frac{J}{gC}$
m= ?
ΔT= Tfinal - Tinitial= 10 C - 15 C= -5 C

Replacing:

-543 J= 0.227 $\frac{J}{gC}$ × m× (-5 C)

Solving:

$m=\frac{-543 J}{0.227 \frac{J}{gC}x(-5 C)}$

m=478.41 grams

In summary, the mass of the sample is 478.41 grams.

Learn more about calorimetry:

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3 years ago

Solids have: fixed shape O A and B fixed size neither A nor B

Lemur [1.5K]

Answer:

B. A and B

Explanation:

1. Solids have a definite volume, definite size and definite shape

2. The particles present in a solid are very closely packed since the intermolecular forces between them are very strong. The molecules do not move apart.

3. Melting point is the temperature at which solid changes into a liquid.

4. When a solid is heated to the melting point the intermolecular forces are overcome by the energy and the molecules present in it moves from its fixed position to take its liquid state which is called as melting.

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4 years ago

A scientist studied a population of gorillas in central Africa for one year. During this time, four gorillas were born and one o

Nat2105 [25]

Answer: zero and had no net change

Explanation:

5 0

4 years ago

Read 2 more answers