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Mademuasel [1]
3 years ago
9

29. Some physical changes involve chemical reactions. TRUE FALSE

Chemistry
1 answer:
Verizon [17]3 years ago
5 0
True. Some physical changes involve chemical reactions. Ice melting is an example of a chemical change in matter
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A _ is a whole number that appears before formula in an equation
Marina CMI [18]
A coefficient is a whole number that appears before the formula in an equation.
7 0
3 years ago
Which isotope will spontaneously decay and emit particles with a charge of +2?
GenaCL600 [577]
(4) 220Fr, known as Francium-220, undergoes alpha decay, which emits an alpha particle, also known as a helium nucleus, which has a charge of +2.
8 0
3 years ago
A hydrate is compound that included water molecules within its crystal structure. During an experiment to determine the percent
stellarik [79]

Answer:

The percent by mass of water in this crystal is:

  • <u>21.4%</u>

Explanation:

This exercise can be easily solved using a simple rule of three where the initial weight of the hydrated crystal (6,235 g) is taken into account as 100% of the mass, and the percentage to which the mass of 4.90 g corresponds (after getting warm). First, the values and unknown variable are established:

  • 6,235 g = 100%
  • 4.90 g = X

And the value of the variable X is found:

  • X = (4.90 g * 100%) / 6,235 g
  • X = approximately 78.6%.

The calculated value is not yet the percentage of the water, since the water after heating the glass has evaporated, therefore, the remaining percentage must be taken, which can be calculated by subtraction:

  • Water percentage = Total percentage - Percentage after heating.
  • <u>Water percentage = 100% - 78.6% = 21.4%</u>
4 0
3 years ago
Read 2 more answers
Suppose you need of Grade 70 tow chain, which has a diameter of and weighs , to tow a car. How would you calculate the mass of t
BabaBlast [244]

Answer: check explanation

Explanation:

In this question we are to find mass. In order to calculate the Mass, We need the values of two parameters, that is, the values given for the grade tow chain, and the value given for the mass per length.

Assuming the mass per length is 3 Kilogram per metre(kg/m) and the grade 70 tow chain length is 5 metre(m).

Therefore, the formula for calculating mass of the chain is given below;

Mass of the chain= mass per unit length(kg/m) × length ---------------------------------------------------------------------------------------------------------------------(1).

Mass of the chain= 3 kg/m × 5 m.

Mass of the chain= 15 kg.

7 0
3 years ago
I NEED HELP ASAP !
Lana71 [14]

Answer:

1.

643.21g  1 mol  6.022^23

262.87 g   1 mol

= 1.4735E24     [Mg3(PO4)2]

2.

4.061x10^24          1mol                22.4 (L)  

6.022^23       1mol

= 151 liters H2O2

3.

479.3g   1 mol   6.022^23

18.02g    1mol

= 1.60E25 H20 atoms

4.

80.34L   1mol       164.1

22.4L       1mol

588.6g   Ca(NO3)2

5.

893.7g   1mol       22.4

44.01g   1mol

= 427 L CO2 or 427.4

6.

5.39 x 10^25     1mol     78.01

6.022^23    1mol

= 6980g Al(OH)3

hope this helps!! :)

8 0
2 years ago
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