The total weight of both objects : 7.035 x 10⁻⁸ kg
<h3>Further explanation</h3>
Given
The weight of a grain of sand : 3.5 x 10⁻¹⁰ kg
The weight of one hair from his eyebrow : 7 x 10⁻⁸ kg
Required
The total weight of both objects
Solution
Scientific Notation consists of 2 parts
1. the first part: the first digit followed by the decimal point
2. The second part: the power of 10 (the exponents).which shows the number of digits after the decimal point
To add/subtract, the exponents must be the same and then add/subtract the coefficient
- convert the largest exponent (7 x 10⁻⁸)
7 x 10⁻⁸ = 700 x 10⁻¹⁰

Answer:
D:Matter is not being conserved because there are 11 units in the reactants, one C8H8 and 10 O2, and 12 units in the products, eight CO2 and four H2O, so there is also more mass in the products that in the reactants.
Explanation:
searched up
Answer:
Neutral substance is the one that neither exhibits acidic properties nor basic. Such a type of substance has equal no. of hydrogen and hydroxyl ions. Due to the neutrality state these substances do not show changes in the indicators.
I did the math i got 220 grams