All categories

2 years ago

What determines the mass number of an element? (2 points)

2 answers:

4 0

The number of neutrons and protons together determines an elements mass number. Therefore, your answer would be C.

hope this helps!

jeyben [28]2 years ago

4 0

The answer is C The total number of neutrons protons

You might be interested in

When PCl5 solidifies it forms PCl4+ cations and PCl6– anions. According to valence bond theory,

rewona [7]

Hey there!

No of hybrid orbitals , H = ( V +S - C + A ) / 2

Where H = no . of hybrid orbitals

V = Valence of the central atom = 5

S = No . of single valency atoms = 4

C = No . of cations = 1

A = No . of anions = 0

For PCl4 +

Plug the values we get H = ( 5+4-1+0) / 2

H = 4 ---> sp3 hybridization

sp3 hybrid orbitals are used by phosphorous in the PCl4+ cations

Answer C

Hope that helps!

3 0

3 years ago

Calculate the average rate of decomposition of NH4NO2 by the reaction 2NH4O5(aq) --> N2(g) H2O(g) at the following time inter

igor_vitrenko [27]

Answer:

$r=-0.033\frac{M}{s}$

Explanation:

Hello!

In this case, since the average rate of reaction is computed as a change given by:

$r=\frac{\Delta [NH_4NO_2 ]}{\Delta t}$

In such a way, given the concentrations at the specified times, we plug them in to obtain:

$r=\frac{(1.48M-4.12M)}{(330s-250s)}\\\\r=-0.033\frac{M}{s}$

Whose negative sign means the concentration decreased due to the decomposition.

Best regards!

6 0

2 years ago

What volume of 1.10 M SrCl2 is needed to prepare 525 mL of 5.00 mM SrCl2?

grigory [225]

Answer:- 2.39 mL are required.

Solution:- It's a dilution problem and to solve this type of problems we use the dilution equation:

$M_1V_1=M_2V_2$

Where, $M_1$ and $M_2$ are molarities of concentrated and diluted solutions and $V_1$ and $V_2$ are their respective volumes.

$M_1$ = 1.10M

$M_2$ = 5.00mM = 0.005M (since, mM stands for milli molar and M stands for molar. 1M = 1000mM)

$V_1$ = ?

$V_2$ = 525 mL

Let's plug in the given values in the formula:

$1.10M(V_1)=0.005M(525mL)$

$V_1=(\frac{0.005M*525mL}{1.10M})$

$V_1=2.39mL$

So, 2.39 mL of 1.10M are needed to make 525 mL of 5.00mM solution.

7 0

2 years ago

Explain how a bond forms between sodium and chlorine in sodium chloride (NaCl).

alexandr1967 [171]

Sodium has 1 valence electron and chlorine has 7 valence electrons and the goal is to get t 8 valence electrons then they attract together, forming table salt.

6 0

2 years ago

Problem Page Gaseous butane will react with gaseous oxygen to produce gaseous carbon dioxide and gaseous water . Suppose 5.2 g o

stich3 [128]

Answer: 0.0 grams

Explanation:

To calculate the moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text {Molar mass}}$

a) moles of butane

$\text{Number of moles}=\frac{5.2g}{58.12g/mol}=0.09moles$

b) moles of oxygen

$\text{Number of moles}=\frac{32.6g}{32g/mol}=1.02moles$

$2C_4H_{10}+13O_2\rightarrow 8CO_2+10H_2O$

According to stoichiometry :

2 moles of butane require 13 moles of $O_2$

Thus 0.09 moles of butane will require = $\frac{13}{2}\times 0.09=0.585moles$ of $O_2$

Butane is the limiting reagent as it limits the formation of product and oxygen is present in excess as (1.02-0.585)=0.435 moles will be left.

Thus all the butane will be consumed and 0.0 grams of butane will be left.

7 0

2 years ago